Jani Sainio

• PhD
• Lecturer at Aalto University

Ammonia (NH3) is a widely used etchant gas in the plasma‐enhanced chemical vapor deposition (PECVD) synthesis of carbon nanofibers (CNFs). In addition to being an effective etchant, NH3 also serves as a dopant by providing N heteroatoms. However, this secondary role has not been comprehensively investigated. Moreover, the influence of N‐doping on t...

The doped Hubbard model is one of the paradigmatic platforms to engineer exotic quantum many-body states, including charge-ordered states, strange metals, and unconventional superconductors. While undoped and doped correlated phases have been experimentally realized in a variety of twisted van der Waals materials, experiments in monolayer materials...

The increasing global demand for energy has led to a rise in the usage of lithium-ion batteries (LIBs), which ultimately has resulted in an ever-increasing volume of related end-of-life batteries. Consequently, recycling has become indispensable to salvage the valuable resources contained within these energy storage devices. While various methods h...

O3‐type NaNi0.8Mn0.1Co0.1O2 (NaNMC811) cathode active materials for sodium–ion batteries (SIBs), with a theoretical high specific capacity (∼ 187 mAh g⁻¹), are in the preliminary exploration stage. This study comprehensively investigates NaNMC811 from multiple perspectives. For the first time, the phase evolution (P3¯m1$P\overline{3}m1$ ‐ Fm3¯m$Fm\...

van der Waals heterostructures have emerged as an ideal platform for creating engineered artificial electronic states. While vertical heterostructures have been extensively studied, realizing high-quality lateral heterostructures with atomically sharp interfaces remains a major experimental challenge. Here, we advance a one-pot two-step molecular b...

There is a need to develop removal strategies for typical battery impurities–iron and aluminum–from actual hydrometallurgical recycling solutions. In this work, the investigated solution originated from lithium nickel manganese cobalt oxide (NMC) rich black mass, while iron phosphate (LFP) was used as an in situ reductant. It was found that the pre...

Van der Waals heterostructures have emerged as an ideal platform for creating engineered artificial electronic states. While vertical heterostructures have been extensively studied, realizing high-quality lateral heterostructures with atomically sharp interfaces remains a major experimental challenge. Here, we advance a one-pot two-step molecular b...

SnOx has received great attention as an electrocatalyst for CO2 reduction reaction (CO2RR), however; it still suffers from low activity. Moreover, the atomic‐level SnOx structure and the nature of the active sites are still ambiguous due to the dynamism of surface structure and difficulty in structure characterization under electrochemical conditio...

Thin layers of commonly used adhesion metals i.e., Cr and Ti were annealed to investigate and estimate their impact on the electrochemical properties of the carbon nanomaterials grown on top...

This research introduces an innovative approach to create a bifunctional oxygen electrocatalyst by using Li-ion battery graphite waste fraction from hydrometallurgical recycling as a raw material.

The use of Li-ion batteries (LIBs) in electrical vehicles and consumer electronics is continuously on the rise which means that the amount of spent LIB (SLIB) is on the rise as well. The sustainable recycling of SLIB for production of secondary resources will prevent the loss of valuable materials and ensures safe and economical management of used...

Composites comprising vanadium-pentoxide (V2O5) and single-walled carbon nanotubes (SWCNTs) are promising components for emerging applications in optoelectronics, solar cells, chemical and electrochemical sensors, etc. We propose a novel, simple, and facile approach for SWCNT covering with V2O5 by spin coating under ambient conditions. With the hyd...

One of the major challenges for in vivo electrochemical measurements of dopamine (DA) is to achieve selectivity in the presence of interferents, such as ascorbic acid (AA) and uric acid (UA). Complicated multimaterial structures and ill-defined pretreatments have been frequently utilized to enhance selectivity. The lack of control over the realized...

Developing highly efficient and robust electrocatalysts for oxygen evolution reaction (OER) is critical to renewable energy technologies. Here, we report an effective strategy to enhance the OER activity of a perovskite electrocatalyst through improving the electrical conductivity introduced by the structural transition. La0.7Sr0.3Fe1−xNixO3−δ (den...

Nanoparticles comprising of transition metals encapsulated in an ultrathin graphene layer ([email protected]) are utilized to anchor very low amount of finely dispersed pseudo-atomic Pt to function as a durable and active electrocatalyst (Pt/[email protected]) for the hydrogen evolution reaction (HER) in acidic media. Our experiments show the vital...

There has been enormous recent interest in heterostructures of two-dimensional van der Waals materials. Integrating materials with different quantum ground states in vertical heterostructures is predicted to lead to novel electronic properties that are not found in the constituent layers. Here, we present direct synthesis of a superconductor-magnet...

We report a cathode material based on plasma‐treated single‐walled carbon nanotubes decorated by RuOx nanoparticles using atomic layer deposition. We have examined cathode performance towards hydrogen evolution reaction by tailoring material wettability, conductivity yielded by plasma‐treatment and the catalyst loading. We discuss that nucleation o...

Mesoporous heteroatom-doped carbon-based nanomaterials are very promising as catalysts for electrochemical energy conversion and storage. We have developed a one-step catalytic chemical vapor deposition method to grow a highly graphitized graphene nanoflake (GF)–carbon nanotube (CNT) hybrid material doped simultaneously with single atoms of N, Co,...

Poor stability restricts the use of polyaniline as a transition-metal-free, high-capacity electrode material for electrochemical energy storage. To improve the durability, methods such as adding a carbonaceous support and thermal treatments have been suggested. Here, we combine both of these approaches and study their effects on the degradation of...

Sulfur is an effective promoter for growing single-walled carbon nanotubes (SWCNTs) and tuning their structural properties. In particular, sulfur has been utilized in the floating-catalyst chemical vapor deposition (FC-CVD) process to fabricate SWCNT-based transparent conductive films (TCFs). However, in-situ catalyst nucleation process in conventi...

The gas-phase atomic/molecular layer deposition (ALD/MLD) technique is strongly emerging as a viable approach to fabricate new exciting inorganic-organic hybrid thin-film materials. However, there have been much less efforts to develop new precursors specifically intended for ALD/MLD; this applies to both the organic and inorganic precursors, and i...

Earth abundant element based inorganic – organic hybrid materials are attractive alternative for electrocatalysing energy conversion reactions. Such material structures do not only increase the surface area and stability of metal nanoparticles (NPs) but also modify the electrocatalytic performance. Here, we introduce, for the first time, multiwall...

Designing earth‐abundant element based efficient and durable electrocatalysts for hydrogen evolution reaction (HER) is attracting growing attention as the renewable electricity supply sector urgently needs sustainable methods for storing energy. Nitrogen functionalized carbon nanomaterials are an interesting electrocatalysts option because of their...

Chalcostibite copper antimony sulfide (CuSbS2) is a promising candidate for application in solar cells. The functionality of CuSbS2 –particles depends on particle size and morphology, and controlling of these two parameters during synthesis process is of uttermost importance. In this work, CuSbS2 particles were prepared by a facile heat-up synthesi...

An MgO supported Co catalyst prepared by atomic layer deposition was applied for the growth of single-walled carbon nanotubes (SWNTs). Different from other catalysts, which generally nucleate SWNTs by base-growth mode, the Co-MgO catalyst uniquely generates SWNTs by tip-growth mode, indicating a weak metal-support interaction. During chemical vapor...

The suitability of the Ni[sbnd]MgO catalyst as a catalyst in chiral-selective growth of single-walled carbon nanotubes (SWNTs) by chemical vapor deposition has been assessed. It reveals that catalyst calcination temperature plays an important role in affecting the catalyst performances. Using CO as the carbon precursor and a chemical vapor depositi...

There is presently a great interest in the development of versatile nanohybrid systems that are based on the covalent functionalization of carbon nanotubes. Covalent functionalization of the single walled carbon nanotubes (SWCNTs) enhances their processability and functionality, allowing them to be further used in different applications. However, a...

Among current technologies for hydrogen production as an environmentally friendly fuel, water splitting has attracted increasing attention. However, the efficiency of water electrolysis is severely limited by the large anodic overpotential and sluggish reaction rate of oxygen evolution reaction (OER). To overcome this issue, the development of effi...

Controlled molecular deposition of natural organic molecules such as nucleobases (NBs) into well-defined thin films represents a progress towards exciting new nanomaterials. The strongly emerging atomic/molecular layer deposition (ALD/MLD) technique provides us with an elegant way to realize the depositions through gas phase with atom-ic/molecular...

Platinum is a metal utilized in many applications. Its catalytic activity can be decreased due to chemical poisoning caused e.g. by phosphorus. To gain more understanding of its poisoning, we present a study of phosphorus adsorption on a platinum (110) single crystal surface. Using X-ray photoelectron spectroscopy, we have found that the adsorbate...

The development of effective and inexpensive hydrogen evolution reaction (HER) electrocatalysts for future renewable energy systems is highly desired. Platinum-based materials are the most active electrocatalysts for catalyzing HER, but reducing the use of Pt is required because of the high price and scarcity of Pt. Here, we achieve pseudo-atomic-s...

Here we show that uracil and sodium form a three-dimensional metal-mediated nucleic acid network; it is grown in atomic/molecular layer-by-layer manner using the atomic/molecular layer deposition (ALD/MLD) thin-film technique. The long-range ordered Na-uracil crystalline structure is evidenced as sharp Bragg reflections. Based on density functional...

Thermodynamically unusual surfaces that possess two contradictory wetting properties, i.e., underoil superhydrophobicity and underwater superoleophobicity, are prepared by the combination of re-entrant topography and delicately matched surface chemistry. The preparation of such extraordinary surfaces relies on two key design criteria and employs a...

MgO supported monometallic Fe (Fe[single bond]MgO) and bimetallic FeMn (FeMn[single bond]MgO) catalysts were developed for growing carbon nanotubes using CO as carbon source. Characterizations on the Fe[single bond]MgO catalyst revealed that Fe cations were well-dispersed in the porous MgO support, forming a solid solution. Since most Fe cations in...

Oxygen evolution reaction (OER) is a critical reaction in electrochemical water splitting and rechargeable metal-air batteries to generate and store clean energy. Therefore, the development of efficient and low cost electrocatalysts for OER with high activity and stability is of great technological and scientific interest. We demonstrate here for t...

Graphene nanoribbons (GNRs)-narrow stripes of graphene-have emerged as promising building blocks for nanoelectronic devices. Recent advances in bottom-up synthesis have allowed production of atomically well-defined armchair GNRs with different widths and doping. While all experimentally studied GNRs have exhibited wide bandgaps, theory predicts tha...

Supplementary Figures 1-5, Supplementary Methods and Supplementary References

Platinum is a well-known catalytic metal whose efficiency can be degraded by the adsorption of impurities. Using different characterization techniques, such as scanning tunnelling microscopy, low-energy electron diffraction and X-ray photoelectron spectroscopy we present a study of phosphorus adsorption on a platinum (111) surface. Under saturation...

Efficient hydrogen evolution reaction (HER) through effective and inexpensive electrocatalysts is a valuable approach for clean and renewable energy systems. Here, single-shell carbon-encapsulated iron nanoparticles (SCEINs) decorated on single-walled carbon nanotubes (SWNTs) are introduced as a novel highly active and durable non-noble-metal catal...

Efficient hydrogen evolution reaction (HER) through effective and inexpensive electrocatalysts is a valuable approach for clean and renewable energy systems. Here, single-shell carbon-encapsulated iron nanoparticles (SCEINs) decorated on single-walled carbon nanotubes (SWNTs) are introduced as a novel highly active and durable non-noble-metal catal...

The ability to gate (i.e., allow or block) droplet and fluid transport in a directional manner represents an important form of liquid manipulation and has tremendous application potential in fields involving intelligent liquid management. Inspired by passive transport across cell membranes which regulate permeability by transmembrane hydrophilic/hy...

Nitrogen-doped graphene nanoplatelets (N-GNP) with 1.6-3.3 at.% nitrogen content were synthesized by thermal annealing of GNP functionalized with a series of imidazole-based nitrogen-containing precursors of different nature, charge and nitrogen content. The imidazole derivatives included one ionic liquid, 1-butyl-3-methylimidazolium tetrafluorobor...

Aligning polymeric nanostructures up to macroscale in facile ways remains a challenge in materials science and technology. Here we show polymeric self-assemblies where nanoscale organization guides the macroscopic alignment up to millimetre scale. The concept is shown by halogen bonding mesogenic 1-iodoperfluoroalkanes to a star-shaped ethyleneglyc...

Atomic layer deposition (ALD) is a thin layer synthesis method applied in this study for preparing carbon-supported mono-metallic Pt- and hi-metallic PtCo catalysts. The catalyst characterization confirmed that small metal particles with a narrow particle size distribution and high metal dispersion were obtained. The location of the metals on the s...

Co/MgO, Co/SiO2 and Co/H beta catalysts were prepared by incipient wetness impregnation. The formation of MgO-CoO solid solution and MgCo2O4 spinel in Co/MgO resulted in high dispersions of Co on MgO even at the low calcined temperatures and the high Co loadings. The second impregnation of Co on Co/MgO enhanced Co cations in surface/subsurface of c...

Low-temperature chemical vapor deposition (CVD) growth of single-walled carbon nanotubes (SWNTs) was achieved on two different types of CoxMg1−xO catalysts prepared by different techniques: atomic layer deposition (ALD) and impregnation. The chirality distribution of SWNTs grown on the ALD-prepared CoxMg1−xO catalyst is wider than that of SWNTs gro...

Atomic layer deposition (ALD) is a thin layer synthesis method applied in this study for preparing carbon-supported mono-metallic Pt- and bi-metallic PtCo catalysts. The catalyst characterization confirmed that small metal particles with a narrow particle size distribution and high metal dispersion were obtained. The location of the metals on the s...

We have studied the incommensurate moir\'e structure of epitaxial graphene grown on iridium(111) by dynamic low energy electron diffraction [LEED-I(V)] and non-contact atomic force microscopy (AFM) with a CO terminated tip. Our LEED-I(V) results yield the average positions of all the atoms in the surface unit cell and are in qualitative agreement w...

We study the properties of Si-rich silicon oxide SiO{sub x} (x < 2) films grown on silica substrates by molecular beam deposition, in a wide range of Si content and annealing temperatures. The measured refractive index and absorption coefficient are successfully described using the effective medium approximation and the chemical compositions measur...

We have studied the adsorption and self-assembly of cobalt phthalocyanine (CoPc) on epitaxial graphene grown on iridium (111) by scanning tunneling microscopy (STM), Auger electron spectroscopy, and low-energy electron diffraction (LEED). CoPc deposited on graphene/Ir(111) at room-temperature self-assembles into large, well-ordered domains with a n...

We have developed a magnesia (MgO)-supported iron-copper (FeCu) catalyst to accomplish the growth of singlewalled carbon nanotubes (SWNTs) using carbon monoxide (CO) as the carbon source at ambient pressure. The FeCu catalyst system facilitates the growth of small-diameter SWNTs with a narrow diameter distribution. UV-vis-NIR optical absorption spe...

To reduce the loading of noble metals on fuel cell catalysts a synthesis method providing evenly distributed nanoparticles on the support surface is needed. Narrow size distribution palladium nanoparticles were prepared on a porous carbon support by atomic layer deposition (ALD), and their activity for ethanol and isopropanol oxidation was studied...

We compare optical and structural properties of silicon-rich silicon oxide (SiOx, x ∼ 1.8) films obtained by ion implantation and molecular beam deposition (MBD). Before annealing, amorphous clusters (≥2 nm) are present in the MBD samples whereas these are absent for ion implantation, and the absorption at 488 nm is much stronger for MBD. Upon anne...

Mixed Fe–Mo oxides are used in industrial catalytic processes of selective oxidation of methanol to formaldehyde. For better understanding of the structure-reactivity relationships of these catalysts we aim to prepare well-ordered iron–molybdate thin films as model catalysts. Here we have studied Mo deposition onto Fe3O4 (111) thin films produced o...

Single-walled carbon nanotubes (SWNTs) have been grown on a silica-supported monometallic nickel (Ni) catalyst at temperatures ranging from as low as 450 °C to 800 °C. Different spectroscopic techniques, such as Raman, photoluminescence emission (PLE), and ultra violet-visible-near infrared (UV-vis-NIR) absorption spectroscopy were used to evaluate...

Chemical vapor deposition of a thin titanium dioxide (TiO2) film on lightweight native nanocellulose aerogels offers a novel type of functional material that shows photoswitching between water-superabsorbent and water-repellent states. Cellulose nanofibrils (diameters in the range of 5–20 nm) with native crystalline internal structures are topical...

SiO(2) supported cobalt (Co) catalyst could be partially reduced and anchored by unreduced Co ions during a carbon monoxide (CO) chemical vapor deposition (CVD) process. This resulted in the formation of sub-nanometre metallic Co clusters catalyzing the growth of single-walled carbon nanotubes (SWNTs) with a narrow diameter distribution.

Epitaxial graphene grown on transition-metal surfaces typically exhibits a moiré pattern due to the lattice mismatch between graphene and the underlying metal surface. We use both scanning tunneling microscopy (STM) and atomic force microscopy (AFM) to probe the electronic and topographic contrast of the graphene moiré on the Ir(111) surface. STM t...

We have developed a magnesia (MgO)-supported iron-copper (FeCu) catalyst to accomplish the growth of single-walled carbon nanotubes (SWNTs) using carbon monoxide (CO) as the carbon source at ambient pressure. The FeCu catalyst system facilitates the growth of small-diameter SWNTs with a narrow diameter distribution. UV-vis-NIR optical absorption sp...

We propose a simple method for the efficient and rapid synthesis of one-dimensional hematite (α-Fe2O3) nanostructures based on electrical resistive heating of iron wire under ambient conditions. Typically, 1–5 μm long α-Fe2O3 nanowires were synthesized on a time scale of seconds at temperatures of around 700 ° ⊂. The morphology, structure, and mech...

We present a fast and effective electrochemical method to purify random networks of single-walled carbon nanotubes (SWCNTs) that leads to total removal of metal catalyst without apparent detrimental effect on the electrochemical properties of the electrodes. The efficiency of the electrochemical purification has been compared with that of conventio...

Nanowires (NWs) of metal oxides (Fe(2)O(3), CuO, V(2)O(5) and ZnO) were grown by an efficient non-catalytic economically favorable method based on resistive heating of pure metal wires or foils at ambient conditions. The growth rate of iron oxide NWs exceeds 100 nm s(-1). Produced NWs were typically 1-5 microm long with diameters from 10 to 50 nm....

The optical properties of silica layers containing silicon nanocrystals are analyzed in terms of spectral filtering in absorbing planar waveguides (cutoff spectra), m-line measurements, and x-ray photoelectron spectroscopy (XPS). The effects of optical dispersion, approximation of weak guiding, and depth dependence of refractive index in a planar w...

Niobia/alumina model catalysts were prepared by physical vapor deposition of Nb in an oxygen atmosphere onto thin alumina films. Structural characterization, performed with scanning tunneling microscopy and infrared reflection absorption spectroscopy, revealed highly dispersed N2O5 nanoparticles exposing Nb{double bond, long}O groups. Thermal stabi...

We have studied the correlation between the chemical state and the oxygen-sensing properties of an iron oxide thin film using a setup that allows simultaneous sensor resistance measurements and X-ray photoelectron spectroscopy (XPS) data acquisition. The gas exposures were performed at the highest operating pressure of the XPS spectrometer at a con...

Self-assembled quantum dots are typically fabricated from compressive-strained material systems, e.g., InAs on GaAs. In this letter, self-assembled quantum dots from tensile-strained GaAsN on InP are demonstrated. GaAsN on InP has type-I band alignment. Stranski-Krastanov growth mode is not observed, but in situ annealing of the uncapped samples re...

The deposition of noble metal particles and films by atomic layer deposition (ALD) has recently gained interest in the fields of catalysis and microelectronics. However, there is little information on the mechanisms governing the reactions of noble metals with high surface area supports. In this work, iridium(III) acetylacetonate was deposited from...

In this work, the use of factor analysis to chemical state quantification of XPS data is studied. First, the theory of the method is reviewed with a special emphasis on the issues related to XPS data analysis. In particular, we concentrate on the transformation of the abstract components into physically meaningful ones in the case where reliable re...

We have investigated chromium layers evaporated onto a thin alumina film at room temperature. The oxidation and reduction behavior of this model catalyst was compared to atomic layer deposition (ALD) and impregnated alumina supported catalysts using X-ray photoelectron spectroscopy (XPS) with a detailed analysis method utilizing asymmetric peak sha...

Quantitative chemical analysis based on X-ray photoelectron spectroscopy (XPS) includes elemental identification and, in many cases, quantification of the chemical states of active surface atoms. The two main parts of the analysis are subtracting the inelastic background and fitting a synthetic lineshape to the data. The analysis of transition meta...

The reduction of alumina-supported chromia with 13 wt.% chromium was investigated by X-ray photoelectron and X-ray absorption spectroscopies, in situ temperature-programmed Raman spectroscopy and in situ temperature-programmed diffuse reflectance infrared Fourier transform spectroscopy combined with mass spectrometry. For comparison, unsupported ch...

First published as an Advance Article on the web 5th August 2003 The reduction of alumina-supported chromia with 13 wt.% chromium was investigated by X-ray photoelectron and X-ray absorption spectroscopies, in situ temperature-programmed Raman spectroscopy and in situ temperature-programmed diffuse reflectance infrared Fourier transform spectroscop...

The initial growth of Co deposited at room temperature on Cuf001g was studied with low energy electron diraction (LEED) and temperature-programmed desorption (TPD). Measured I(V) spectra were compared with calculated spectra from several model structures, including substitutionally disor- dered alloys. The averaged T-matrix approximation (ATA) was...

We have investigated the growth and reactivity of chromium layers deposited onto a thin alumina film at room temperature and at 570 K. The interaction between Cr and the Al2O3/NiAl(110) surface leads to partial oxidation to Cr2+ and Cr3+ species. Complete oxidation to Cr3+ was achieved using moderate O2 doses at room temperature in vacuum. Cr has a...

We have studied metallic and oxidized chromium layers on thin ordered alumina films grown on a NiAl110 substrate using x-ray photoelectron spectroscopy. The interaction between the chromium layers and the substrate has been characterized after deposition at room temperature and after oxidation at 300 and 700 K. Our results indicate partial oxidatio...

Vacuum created model systems give the possibility for detailed study of the substrate–adsorbate interaction. In this work two systems have been created by vacuum deposition and these have been characterized with different electron spectroscopies. A chromium oxide model catalyst has been studied with X-ray photoelectron spectroscopy (XPS) and a magn...