Maarten Roeffaers

KU Leuven | ku leuven · Department of Microbial and Molecular Systems (M²S)

In this study, we explore the efficacy of gold (Au) as a selective electrocatalyst for the reduction of nitrate to hydroxylamine, a valuable nitrogen-based chemical, while also evaluating the by-product...

Fiber-optic surface plasmon resonance (FO-SPR) sensors look at the absorbance of reflected light to measure changes in refractive index (RI). FO-SPR sensor modeling is essential in understanding the underlying processes that induce such RI changes. Despite two types of rays, i.e., skew and meridional rays, an FO-SPR model has been developed in the...

Solar-light driven oxidation of benzylic alcohols over photocatalysts endows significant prospects in value-added organics evolution owing to its facile, inexpensive and sustainable process. However, the unsatisfactory performance of actual photocatalysts due to the inefficient charge separation, low photoredox potential and sluggish surface reacti...

Designing photoluminescence sensing devices for gaseous oxygen that combine ease of acquisition with efficient performance is a critical yet challenging task. Herein, a novel oxygen‐sensing probe based on zeolite Y confined silver clusters prepared via a simple approach, is proposed. The large Ag6 clusters formed after hydrogenation exhibit a brigh...

Metal halide perovskite (MHP) quantum dots (QDs) offer immense potential for several areas of photonics research due to their easy and low‐cost fabrication and excellent optoelectronic properties. However, practical applications of MHP QDs are limited by their poor stability and, in particular, their tendency to aggregate. Here, we develop a two‐st...

The electrocatalytic conversion of inert CO2 to value‐added chemical fuels powered by renewable energy is one of the benchmark approaches to address excessive carbon emissions and achieve carbon‐neutral energy restructuring. However, the adsorption/activation of supersymmetric CO2 is facing insurmountable challenges that constrain its industrial‐sc...

Metal nanoparticle (NP) cocatalysts are widely investigated for their ability to enhance the performance of photocatalytic materials; however, their practical application is often limited by the inherent instability under light irradiation. This challenge has catalyzed interest in exploring high‐entropy alloys (HEAs), which, with their increased en...

The validity of N 2 reduction experiments relies on control experiments with isotopically labeled ¹⁵ N 2 . Here we discovered significant ¹⁵ NH 3 contamination (73ppm) in commercial ¹⁵ N 2 and also observed the prescence of...

Functionalizing sp3 C-H bonds in toluene through photocatalysis poses a significant challenge in organic synthesis, garnering substantial research attention. Nevertheless, the inert nature of the C-H bond restricts the photocatalytic...

Coke formation is the prime cause of catalyst deactivation, where undesired carbon wastes block the catalyst surface and hinder further reaction in a broad gamut of industrial chemical processes. Yet, the origins of coke formation and their distribution across the catalyst remain elusive, obstructing the design of coke‐resistant catalysts. Here, we...

Small metal oligomers have gained significant attention due to their exceptional optoelectronic properties and versatile applications, ranging from sensors to imaging and catalysis. However, the need for matrices (silica, zeolites, or metal‐organic frameworks) to prevent aggregation into larger metallic particles reduces their potential applicabili...

The electrocatalytic nitrate (NO3–) reduction reaction (eNITRR) is a promising method for ammonia synthesis. However, its efficacy is currently limited due to poor selectivity, largely caused by the inherent complexity of the multiple-electron processes involved. To address these issues, oxygen-vacancy-rich LaFe0.9M0.1O3−δ (M = Co, Ni, and Cu) pero...

The electronic age demands the development of high-performing thin-film semiconductors that are low-cost and scalable. Lead (Pb)-based halide perovskites (LHPs) have proven to be successful in this regard, but their use is limited by environmental and health concerns related to lead toxicity. Lead-free halide compounds offer a promising alternative...

Nanocrystals (NCs) of inorganic lead halide perovskites with narrow emission line widths hold great potential for next-generation color-saturated optoelectronic devices. However, their stability and electroluminescence performance are currently hindered by environment-dependent structure deterioration over time and inferior carrier transport. These...

The frequency of reports utilizing synchrotron‐based grazing incident wide angle X‐ray scattering (GIWAXS) to study metal halide perovskite thin films has exploded recently, as this technique has proven invaluable for understanding several structure‐property relationships that fundamentally limit optoelectronic performance. The GIWAXS geometry and...

The adverse health effects of ambient carbonaceous particles (CPs) such as carbon black (CB), black carbon (BC), and brown carbon (BrC) are becoming more evident and depend on their composition and emission source. Therefore, identifying and quantifying these particles in biological samples are important to better understand their toxicity. Here, w...

All‐inorganic lead‐free Cs2AgBiBr6 double perovskites have gained significant attention due to their potential as stable and nontoxic photoactive semiconductors. Currently, it remains challenging to synthesize homogeneous microcrystals (MCs) exhibiting excellent properties, which are necessary for large‐area device integration. This work proposes a...

Metal-halide perovskites (MHPs) exhibit excellent properties for application in optoelectronic devices. The bottleneck for their incorporation is the lack of long-term stability such as degradation due to external conditions (heat, light, oxygen, moisture, and mechanical stress), but the occurrence of phase transitions also affects their performanc...

Surface passivation by post-treatment with methylammonium chloride (MACl) is regarded as a promising strategy to suppress surface defects in organic-inorganic lead halide perovskites and elevate the efficiency of solar cells based on these materials. However, traditional MACl post-treatment methods often impede the performance of the final device,...

Engineering crystal structure of Cs3BiBr6 and Cs3Bi2Br9 is theoretically and experimentally demonstrated to modulate their photocatalytic performance. This work offers insights into the structure-photoactivity relationships of metal halide perovskites (MHPs) and provides a guideline for exploiting MHPs toward efficient photocatalytic organic synthe...

Metal Nanocatalysts Nanocatalysts are monitored by an innovative characterization toolkit at nano‐, meso‐ and bulk‐scales to decode nanoparticle sintering. The lifetime of a nanoparticle heavily depends on its crystal orientation on the support and its mesoscale environment, yielding guidelines for future catalyst design. More details can be found...

Lead halide perovskites are promising candidates for high-performance light-emitting diodes (LEDs); however, their applicability is limited by their structural instability toward moisture. Although a deliberate addition of water to the precursor solution has recently been shown to improve the crystallinity and optical properties of perovskites, the...

Noble metal nanoparticles are often used as cocatalysts to enhance the photocatalytic efficiency. While the effect of cocatalyst nanoparticle size and shape has widely been explored, the effect of the crystal phase is largely overlooked. In this work, we investigate the effect of Ru nanoparticle crystal phase, specifically regular hexagonal close-p...

Noble metal nanoparticles are often used as cocatalysts to enhance the photocatalytic efficiency. While the effect of cocatalyst nanoparticle size and shape has widely been explored, the effect of the crystal phase is largely overlooked. In this work, we investigate the effect of Ru nanoparticle crystal phase, specifically regular hexagonal close-p...

Correction for ‘Atomic-scale detection of individual lead clusters confined in linde type A zeolites’ by Jarmo Fatermans et al. , Nanoscale , 2022, 14 , 9323–9330, https://doi.org/10.1039/D2NR01819E.

The black perovskite phase of CsPbI3 is promising for optoelectronic applications; however, it is unstable under ambient conditions, transforming within minutes into an optically inactive yellow phase, a fact that has so far prevented its widespread adoption. Here we use coarse photolithography to embed a PbI2-based interfacial microstructure into...

Polymer solar cells (PSCs) have seen rapid progress in recent years, whereby the mixture of polymer donors and small-molecule acceptors (SMAs) are fine-tuned to realize a favorable kinetically trapped morphology and thus a commercially viable device efficiency. However, the thermodynamic relaxation of the mixed domains within the blend raises conce...

Metal nanoparticle (NP) sintering is a prime cause of catalyst degradation, limiting its economic lifetime and viability. To date, sintering phenomena are interrogated either at the bulk scale to probe averaged NP properties or at the level of individual NPs to visualize atomic motion. Yet, “mesoscale” strategies which bridge these worlds can chart...

Among the different air pollutants, particulate matter (PM) is of great concern due to its abundant presence in the atmosphere, which results in adverse effects on the environment and human health. The different components of PM can be classified based on their physicochemical properties. Carbonaceous particles (CPs) constitute a major fraction of...

Background Maternal exposure to particulate air pollution during pregnancy has been linked to multiple adverse birth outcomes causing burden of disease later in the child's life. To date, there is a paucity of data on whether or not ambient particles can both reach and cross the human placenta to exert direct effects on fetal organ systems during g...

Developing light‐harvesting materials with broad spectral response is of fundamental importance in full‐spectrum solar energy conversion. We found that, when a series of earth‐abundant metal (Cu, Co, Ni and Fe) salts are dissolved in coordinating solvents uniformly dispersed nanodots (NDs) are formed rather than fully dissolving as molecular specie...

Zeolite confined silver clusters (AgCLs) have attracted extensive attention due to their remarkable luminescent properties, but the elucidation of the underlying photophysical processes and especially the excited-state dynamics remains a challenge. Herein, we investigate the bright photoluminescence of AgCLs confined in Linde Type A zeolites (LTA)...

Cs3Bi2Br9 decorated with crystalline-amorphous Pd nanocubes as cocatalyst is reported to photocatalytically coproduce ca. 1400 μmol h−1 g−1 of H2 and benzaldehyde from the selective benzyl alcohol oxidation. This route...

Developing light‐harvesting materials with broad spectral response is of fundamental importance in full‐spectrum solar energy conversion. We found that, when a series of earth‐abundant metal (Cu, Co, Ni and Fe) salts are dissolved in coordinating solvents uniformly dispersed nanodots (NDs) are formed rather than fully dissolving as molecular specie...

Detection and size estimation of combustion-derived carbonaceous particles (CDCPs) are important to understand their toxicity. Size determination of individual nano- and microparticles (NMPs) based on scattered light is a straightforward method. However, detection and sizing of CDCPs in biological samples based on scattering alone are not possible...

Organic solar cells (OSCs) have experienced rapid progress with the innovation of near‐infrared (NIR)‐absorbing small‐molecular acceptors (SMAs), while the unique electronic properties of the SMAs raise new challenges in relation to cathode engineering for effective electron collection. To address this issue, we synthesized two fluorinated perylene...

Photocatalytic H2 evolution from haloid acid (HX) solution by metal halide perovskites (MHPs) has been intensively investigated; however, the corrosive acid solution severely restricts its practical operability. Therefore, developing acid-free schemes for H2 evolution using MHPs is highly desired. Here, we investigate the photocatalytic anaerobic d...

Detection and size estimation of combustion-derived carbonaceous particles (CDCPs) are important to understand their toxicity. Size determination of individual nano- and microparticles (NMPs) based on scattered light is a straightforward method. However, detection and sizing of CDCPs in biological samples based on scattering alone are not possible...

Structural analysis of metal clusters confined in nanoporous materials is typically performed by X-ray-driven techniques. Although X-ray analysis has proved its strength in the characterization of metal clusters, it provides averaged structural information. Therefore, we here present an alternative workflow for bringing the characterization of conf...

We demonstrate a new case of materials–gene engineering to precisely design photocatalysts with the prescribed properties. Based on theoretical calculations, a phase‐doping strategy was proposed to regulate the pathways of CO2 conversion over Au nanoparticles (NPs) loaded TiO2 photocatalysts. As a result, the thermodynamic bottleneck of CO2‐to‐CO c...

With fascinating photophysical properties and a strong potential to utilize solar energy, metal halide perovskites (MHPs) have become a prominent feature within photocatalysis research. However, the effectiveness of single MHP photocatalysts is relatively poor. The introduction of a second component to form a heterojunction represents a well‐establ...

We demonstrate a new case of materials‐gene engineering to precisely design photocatalysts with the prescribed properties. Based on theoretical calculations, a phase‐doping strategy was proposed to regulate the pathways of CO2 conversion over Au nanoparticles (NPs) loaded TiO2 photocatalysts. As a result, the thermodynamic bottleneck of CO2‐to‐CO c...

Cd1−xZnxS solid solutions with strong light absorption are promising materials for solar-driven CO2 reduction; however, their relatively weak redox ability and intrinsic photo-corrosion limit their further development as a photocatalyst. The addition of a second photocatalyst with a suitable band structure to construct a S-scheme photocatalytic sys...

With fascinating photophysical properties and strong potential to utilize solar energy, metal halide perovskites (MHPs) have become a prominent feature within photocatalysis research. However, the effectiveness of single MHP photocatalysts is relatively poor. The introduction of a second component to form a heterojunction represents a well‐establis...

Metal halide perovskites (MHPs) have been widely investigated for various photocatalytic applications. However, the dual-functional reaction system integrated selective organic oxidation with H2 production over MHPs is rarely reported. Here, we demonstrate for the first time the selective oxidation of aromatic alcohols to aldehydes integrated with...

Crystal phase engineering of metal nano and microparticles is a new and promising route to tune their properties, complementary to their often exploited optimization via size and shape control. Ag...

Recently, the detection and quantification of humidity has attracted great interest, but for fluorescence sensing of humidity, it is still a challenge to achieve high-performance. Here, we report an ultrasensitive...

Due to the high stability and chemical inertia of methane, CH4, its selective conversion into value-added organic chemicals under mild conditions has been widely regarded as an important reaction for the chemical industry. Here, we develop a RuOx decorated ZnO/CeO2 photocatalyst for the highly efficient and selective transformation of CH4 into CH3O...