Chunhua Cui

University of Electronic Science and Technology of China | UESTC · Institute of Fundamental and Frontier Sciences

Shape-selective monometallic nanocatalysts offer activity benefits based on structural sensitivity and high surface area. In bimetallic nanoalloys with well-defined shape, site-dependent metal surface segregation additionally affects the catalytic activity and stability. However, segregation on shaped alloy nanocatalysts and their atomic-scale evol...

Morphological shape in chemistry and biology owes its existence to anisotropic growth and is closely coupled to distinct functionality. Although much is known about the principal growth mechanisms of monometallic shaped nanocrystals, the anisotropic growth of shaped alloy nanocrystals is still poorly understood. Using aberration-corrected scanning...

Cuδ+ sites on the surface of oxide-derived copper (OD-Cu) are of vital importance in electrochemical CO2 reduction reaction (CO2RR). However, the underlying reason for the dynamically existing Cuδ+ species, although thermodynamically unstable under reductive CO2RR conditions, remains uncovered. Here, by using electron paramagnetic resonance, we ide...

Strategies to generate high-valence metal species capable of oxidizing water often employ composition and coordination tuning of oxide-based catalysts, where strong covalent interactions with metal sites are crucial. However, it remains unexplored whether a relatively weak “non-bonding” interaction between ligands and oxides can mediate the electro...

Atomically dispersed supported catalysts can maximize atom efficiency and minimize cost. In spite of much progress in gas-phase catalysis, applying such catalysts in the field of renewable energy coupled with electrochemistry remains a challenge due to their limited durability in electrolyte. Here, we report a robust and atomically dispersed hybrid...

Electrochemical chlorine evolution reaction is of central importance in the chlor-alkali industry, but the chlorine evolution anode is largely limited by water oxidation side reaction and corrosion-induced performance decay in strong acids. Here we present an amorphous CoOxCly catalyst that has been deposited in situ in an acidic saline electrolyte...

Selective electrochemical upgrading of CO2 to multicarbon (C2+) products requires a C-C coupling process, yet the underlying promoting mechanism of widely involved Cu oxidation states remains largely unclear, hindering the subtle design of efficient catalysts. Herein, we unveil the critical role of Cu+ in promoting C-C coupling via coordination wit...

Selective CH4 oxidation to CH3OH or HCHO with O2 in H2O under mild conditions provides a desired sustainable pathway for synthesis of commodity chemicals. However, manipulating reaction selectivity while maintaining high productivity remains a huge challenge due to the difficulty in the kinetic control of the formation of a desired oxygenate agains...

Tungsten trioxide (WO3) is one of the promising semiconductors suitable for photoelectrochemical water oxidation, but its hydroxyl radical (•OH)-induced intrinsic performance degradation remains unclarified. Here, we demonstrate that quenching-treated WO3 with preferred {021} facets shows a highly improved Faradaic efficiency (from 57 to 95%) and i...

Photoelectrochemical (PEC) water splitting in acid is promising, but its development has been hindered by the lack of stable photoanodes and effective nonprecious cocatalysts. WO3 is one of the few acid-stable semiconductors, but its fast performance decay under illumination remains elusive and unsolved. Herein, we present that the fast photo-curre...

The energy efficiency of water electrolysis is limited by the sluggish reaction kinetics of the anodic oxygen evolution reaction (OER). To overcome this limitation, OER can be replaced by a less demanding oxidation reaction, which in the ideal scenario could be even used to generate additional valuable chemicals. Herein, we focus on the electrochem...

A substantial effort is devoted to the development of efficient electrolyzers made of earth-abundant elements for low-temperature industrial-scale water electrolysis. However, a large current density leads to the decline of the reaction kinetics that result from the decrease of local pH, the irreversible redox states of active metal sites, and the...

Atomically ordered intermetallic nanoparticles are promising for catalytic applications but are difficult to produce because the high-temperature annealing required for atom ordering inevitably accelerates metal sintering that leads to larger crystallites. We prepared platinum intermetallics with an average particle size of <5 nanometers on porous...

While self-healing is considered a promising strategy to achieve long-term stability for oxygen evolution reaction (OER) catalysts, this strategy remains a challenge for OER catalysts working in highly alkaline conditions. The self-healing of the OER-active nickel iron layered double hydroxides (NiFe-LDH) has not been successful due to irreversible...

We report a regenerable and redox-inactive ZnOxHy layer that was in-situ deposited onto metal oxides MOz (M=Co, Fe, and Ni) in alkaline media containing [Zn(OH)4]2- species during water oxidation. An interface dipole was developed at the MOz/Zn interface, resulting in a decrease of the OER overpotential. Exemplified by CoOz/ZnOxHy bilayer structure...

The electrocatalytic methanol conversion is of importance in direct methanol fuel cell, biomass reforming, and hydrogen generation. To achieve a “carbon-neutral” target, CO2 byproducts derived from biofuels should be mitigated. In contrast to the complete oxidation of methanol to CO2, the selective oxidation of methanol to formate is a CO2-emission...

Perovskite oxide is a promising alternative to noble metal electrocatalysts for the oxygen evolution reaction (OER). However, as one of the most active oxide catalysts, cubic SrCoO3 presents poor OER performance relative to the theoretically predicted activity. Appropriate introduction of a guest component in the lattice and surface could largely p...

The fermentation of biomass allows for the generation of major renewable ethanol biofuel that has high energy density favorable for direct alcohol fuel cells in alkaline media. However, selective conversion of ethanol to either CO2 or acetate remains a great challenge. Especially, the ethanol-to-acetate route usually demonstrates decentoxidation cu...

In article number 2006623, Andreu Cabot, Chunhua Cui, and co‐workers present nickel iron diselenide nanorods, which are produced in solution and used electrocatalytically to convert methanol to formate at a high rate and with a Faradaic conversion efficiency of 99%. This work demonstrates the highly efficient and selective methanol‐to‐formate conve...

The electro‐oxidation of methanol to formate is an interesting example of the potential use of renewable energies to add value to a biosourced chemical commodity. Additionally, methanol electro‐oxidation can replace the sluggish oxygen evolution reaction when coupled to hydrogen evolution or to the electroreduction of other biomass‐derived intermed...

Although much is known about the increased rate of a catalyst required for the oxygen evolution reaction (OER), the hole accumulation behaviors of the catalyst on both photo- and dark-electrodes remain uncovered. We present a rational tuning of the hole-accumulation and hole-transfer ability of a catalyst by in-situ deposition of IrOx on NiOx islan...

Highly active Ni3C branched particles are demonstrated and their selective electrocatalytic conversion of methanol to formate is probed by using advanced in situ infrared spectroscopy combined with nuclear magnetic resonance spectroscopy. Abstract A methanol economy will be favored by the availability of low‐cost catalysts able to selectively oxid...

A methanol economy will be favored by the availability of low cost catalysts able to selective oxidize methanol to formate. This selective oxidation would allow extracting the largest part of the fuel energy while simultaneously producing a chemical with even higher commercial value than the fuel itself. Here we present a highly active methanol ele...

Transition metal (oxy)hydroxides with abundance of redox metal sites are important for the development of electrochromic devices, rechargeable metal-air batteries, pseudo-capacitors and industrial electrolyzers. The robust charging reversibility of the redox metal sites ensures long-term durability of the devices, but remains unachieved and usually...

The Ni/CoOx sites were supported on around 2 nm-TiOx modified hematite photoanode for water oxidation. TiOx demonstrates an insignificant hole accumulation and a catalytically inactive surface that serves as an...

Most transition metal-based oxygen-evolving catalysts surface typically experiences irreversible compositional and structural variations during oxygen evolution reaction (OER) in hydrolytic and corrosive alkaline media, degrading the coordination environment of active metal sites into unified (oxy)hydroxides. Here we present an in situ electrochemi...

Cocatalysts are usually deposited on semiconductors to accelerate charge transfer/separation and passivate their surface states. Although various methods have been developed to decorate cocatalysts on semiconductors, in situ depositing a transition metal oxide/oxyhydroxide catalyst in alkaline electrolyte remains a challenge. Herein, we present a f...

In modern technologies, the researchers are keen on top-down approaches to tailor the materials from bulk into their nanometer forms. For the amorphous alumina, this is the other way around. The amorphous alumina was receiving attention in the forms of thin films or nanoparticles many years ago, yet any attempts to increase the dimensions destabili...

(Figure Presented) We present a voltammetric, spectroscopic, and atomic-scale microscopic study of how initial interfacial contact with high- and low-pH electrolytes affects the surface voltammetry, near-surface composition, CO binding, and electrocatalytic oxygen reduction reaction (ORR) of dealloyed Pt-Ni alloy nanoparticles deployed in fuel cell...

Co-based nanomaterials have been intensively explored as promising noble metal free oxygen evolution reaction (OER) electrocatalysts. Herein, we first report phase selective synthesis of novel hierarchical CoTe2 and CoTe nanofleeces for efficient OER catalyst. The CoTe2 nanofleeces exhibited excellent electrocatalytic activity and stablity for OER...

Co-based nanomaterials have been intensively explored as promising noble metal free oxygen evolution reaction (OER) electrocatalysts. Herein, we first report phase selective synthesis of novel hierarchical CoTe2 and CoTe nanofleeces for efficient OER catalyst. The CoTe2 nanofleeces exhibited excellent electrocatalytic activity and stablity for OER...

Hetero-interface tailoring is of importance for the catalytic activity enhancement of nanomaterials in various reactions owing to the charge polarization at the interface. We report an accurate manipulation of a replacement reaction for Pt/PtTe hetero-nanowire (NW) and PtTe NW fabrication. Their geometric structures are controlled by using the aged...

Dealloyed Pt bimetallic core-shell catalysts derived from low-Pt bimetallic alloy nanoparticles (e.g, PtNi3 ) have recently shown unprecedented activity and stability on the cathodic oxygen reduction reaction (ORR) under realistic fuel cell conditions and become today's catalyst of choice for commercialization of automobile fuel cells. A critical s...

The development of economic water oxidation catalysts is a key step towards large-scale water splitting. However, their current exploration remains empirical to a large extent. Elucidating the correlations between electronic properties and catalytic activity is crucial for deriving general and straightforward catalyst design principles. Herein, str...

We performed in situ transmission electron microscopy of phase-segregated octahedral Pt-Ni alloy fuel cell nanocatalysts under thermal annealing to study their morphological stability and surface compositional evolution. The pristine octahedral Pt-Ni nanoparticles (NPs) showed Pt-rich corners/edges and slightly concave Ni-rich {111} facets. Time-re...

The chemical and morphological stability of size- and shape-selected octahedral PtNi nanoparticles (NP) were investigated after different annealing treatments up to a maximum temperature of 700°C in vacuum and under 1 bar of CO. Atomic force microscopy (AFM) was used to examine the mobility of the NPs and their stability against sintering, and X-ra...

Hollow alloyed nanoparticles (NPs) represent one kind of promising fuel cell electrocatalysts. However, the formation of single-cavity hollow structures by dealloying process is quite challenging owing to the random leaching/dissolution of transition metal, surface passivation and the limited diffusion distance of noble metals. Here we present a fa...

Dealloyed, that is, selectively leached Pt-based oxygen reduction reaction (ORR) nanoparticle catalysts have demonstrated previously unachieved initial reactivity and performance durability in single cell of PEM fuel cells. Dealloying is typically achieved using free corrosion in acid or electrochemical cycling. Here, we explore dealloying at const...

This study intends to provide some insight in the up-to-date elusive assessment of a correct choice of method for estimating the active surface area of Pt alloy nanoparticle catalysts. Taking PtNi3 nanoparticles as an example, we have compared three types of electrochemically active surface area (ECSA) data, CO-ECSA, Hupd-ECSA, and Hupd/CO-ECSA, wh...

Compositional segregation is an important physical phenomenon in alloy materials and has significant influences on their physical and chemical properties. In particular, segregation at the surface or subsurface can drastically change the molecular adsorption properties of alloy surfaces and thus becomes a promising way to design highly active catal...

Colloid-based chemical synthesis methods of bimetallic alloy nanoparticles (NPs) provide good monodispersity, yet generally show a strong variation of the resulting mean particle size with alloy composition. This severely compromises accurate correlation between composition of alloy particles and their size-dependent properties. To address this iss...

We review our recent progress in the development of Pt–Ni bimetallic electrocatalysts with both high sustained activity and sustained stability for oxygen reduction reaction (ORR). This was achieved by an atomic understanding and rational control of the core–shell compositional patterns and size-related nanoporosity within the bimetallic nanopartic...

Using aberration-corrected scanning transmission electron microscopy and electron energy loss spectroscopy, we present atomic-scale insights into the size-dependent degradation of Pt-Ni bimetallic oxygen reduction catalysts. We revealed that how particle size can influence the evolution of nanoporosity in the bimetallic nanoparticles and, consequen...

We present the design and synthesis of phase segregated Pt alloy nanoparticle electrocatalysts through a facile solvothermal route in a dimethylformamide solvent. The compositional segregation near the alloyed PtNi nanoparticle surface was achieved by controlling the reaction kinetics and site-dependent compositional segregation in the facet center...

We present the synthesis and controlled dealloying of homogeneously alloyed well-dispersed PtNi3 nanoparticles. This material was studied by dealloying at various constant potentials for 24 hours in order to investigate structural changes as function of electrode potentials. Using electrochemical analysis techniques we have provided evidence that t...

Monodisperse PdCu nanocubes for ORR: Uniform PdCu nanocubes with a side length of 12 nm can be synthesized through a one-pot colloidal synthesis. These cubes display a substantially enhanced oxygen reduction reaction (ORR) activity compared with that of PdCu nanoparticles, Pd nanoparticles, and commercial Pt/C catalysts.

A study of the morphological and chemical stability of shape-selected octahedral Pt0.5Ni0.5 nanoparticles (NPs) supported on highly-oriented pyrolytic graphite (HOPG) is presented. Ex situ atomic force microscopy (AFM) and in situ X-ray photoelectron spectroscopy (XPS) measurements were used to monitor the mobility of Pt0.5Ni0.5 NPs and to study lo...

Thermal annealing is an important and widely adopted step during the synthesis of Pt bimetallic fuel‐cell catalysts, although it faces the inevitable drawback of particle sintering. Understanding this sintering mechanism is important for the future development of highly active and robust fuel‐cell catalysts. Herein, we studied the particle sinterin...

Pt-Ni alloy nanocrystals with controlled architectures (multi-arms and flowers) have been synthesized via a simple colloid chemistry method. The crystal surfaces possess abundant low-coordination defect sites, where the reaction kinetics of methanol oxidation can be improved, resulting in the catalysts exhibiting better stability and higher resista...

In this chapter, we review the studies of metal and alloy catalyst surfaces reconstructed in ultra-high vacuum (UHV) and gaseous conditions with respectively elevated temperatures and in electrochemical environments at room temperature and the electrochemical activities of these surface-restructured catalysts. We firstly summarize the geometric and...

Ultrathin and ultralong: Highly uniform, ultrathin (diameter 5-7 nm), and ultralong (aspect ratio >10(4) ) PtPdTe nanowires (NWs) were synthesized by using a facile method employing Te NWs as both sacrificial templates and reducing agents. Fine-tuning of the molar ratios of Pt and Pd precursors afforded PtPdTe NWs with different compositions and en...

Solid surfaces generally respond sensitively to their environment. Gas phase or liquid phase species may adsorb and react with individual surface atoms altering the solid-gas and solid-liquid electronic and chemical properties of the interface. A comprehensive understanding of chemical and electrochemical interfaces with respect to their responses...

Skinnier than a supermodel: There will be an optimal size for ultrathin alloyed nanowires (NWs) as electrocatalysts. The ultrathin size of the NWs maximizes the surface area and utilization of precious metals, thereby lowering the precious metals loading and reducing the cost while increasing their electroactivity and stability.

In order for fuel cells to have commercial viability as alternative fuel sources, researchers need to develop highly active and robust fuel cell electrocatalysts. In recent years, the focus has been on the design and synthesis of novel catalytic materials with controlled interface and surface structures. Another goal is to uncover potential catalyt...

Branched Pd nanodendrites have been synthesized by a very simple method, which have displayed substantially enhanced oxygen reduction reaction (ORR) activity compared with that of commercial Pd/C catalysts. The Pd nanodendrites show 4.8 times more activity on the basis of an equivalent noble metal mass for the ORR than the commercial Pd/C catalysts...

The active site-dependent electrochemical formic acid oxidation was evidenced by the increased coverage of Pt in the topmost mixed PtPd alloy layer of ternary PtPdCu upon potential cycling, which demonstrated two catalytic pathways only in one catalyst owing to surface atomic redistribution in an acidic electrolyte environment.

We demonstrate how shape-selectivity and optimized surface composition result in exceptional oxygen reduction activity of octahedral Pt-Ni nanoparticles (NPs). The alloy octahedra were obtained utilizing a facile completely surfactant-free solvothermal synthesis. We show that the choice of precursor ligands controls the shape, while the reaction ti...

Good things come in threes: Ternary PtPdCu electrocatalysts were formed through surface‐atomic redistribution under potential cycling. This redistribution modified the surface electronic structure and adsorbate bond energy, thus changing the electrocatalytic activity for the oxygen‐reduction reaction.

We report a first solution strategy for controlled synthesis of Adams' catalyst (i.e., α-PtO(2)) by a facile and totally green approach using H(2)PtCl(6) and water as reactants. The prepared α-PtO(2) nanocrystals (NCs) are ultrasmall in size and have very "clean" surfaces, which can be reduced to Pt NCs easily in ethanol under ambient conditions. S...

A facile and totally green approach has been discovered for controlled synthesis of Adams' catalyst (i.e., α‐PtO2) by only using H2PtCl6 and water as reactants; these particles can be easily reduced to Pt nanocrystals (NCs) in ethanol under ambient conditions. The obtained contaminant‐free NCs all exhibit higher activities and stabilities for oxyge...

IntroductionGalvanic Replacement MethodHard Template-Directed MethodSoft Template-Directed Method Conclusions and OutlookReferences

We report the enhanced activity and stability of CuPt bimetallic tubular electrocatalysts through potential cycling in acidic electrolyte. A series of CuPt tubular electrocatalysts with sequential increased lattice ordering and surface atomic fraction of Pt were designed and synthesized by thermal annealing to reveal their improved electrocatalytic...

Thermosensitive poly(N-isopropylacrylamide) (PNIPAM)/Au nanoparticle (NP) nanocomposite hydrogels are synthesized by in situ γ-radiation-assisted polymerization of N-isopropylacrylamide monomer aqueous solution in the presence of HAuCl₄·4H₂O. In this reaction, the PNIPAM hydrogels and the Au NPs are formed simultaneously, thus demonstrating an easy...

We report the enhanced activity and stability of CuPt bimetallic tubular electrocatalysts through potential cycling in acidic electrolyte. A series of CuPt tubular electrocatalysts with sequential increased lattice ordering and surface atomic fraction of Pt were designed and synthesized by thermal annealing to reveal their improved electrocatalytic...

Macroscale elastomeric conductors composed of sponge-like three-dimensional silver-carbon hybrid nanocable/carbon nanotube networks can be fabricated through the template role of hydrothermally synthesized silver-cross-linked poly(vinyl alcohol) coaxial nanocable artificial sponges. The obtained elastomeric conductors exhibit excellent elasticity,...

We report a large scale restructuring of porous Pt-Ni nanoparticle tubes for electrocatalytic oxidation of methanol, showing high catalytic activity, stability and resistance to poisoning. The surface restructuring highly improved the electrochemical active surface area (ECSA) by potential cycling in a strong acid electrolyte at room temperature. A...