A5020337283- Electrocatalysts for Energy Conversion
- Advanced Photocatalysis Techniques
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Electrochemical Analysis and Applications
- Catalytic Processes in Materials Science
- CO2 Reduction Techniques and Catalysts
- Gas Sensing Nanomaterials and Sensors
- Advanced battery technologies research
- Transition Metal Oxide Nanomaterials
- Iron oxide chemistry and applications
- Metal complexes synthesis and properties
- Copper-based nanomaterials and applications
- Water Quality Monitoring and Analysis
- Ga2O3 and related materials
- TiO2 Photocatalysis and Solar Cells
- Conducting polymers and applications
- Perovskite Materials and Applications
- Metal-Catalyzed Oxygenation Mechanisms
- Nanomaterials for catalytic reactions
- Organometallic Complex Synthesis and Catalysis
- Polyoxometalates: Synthesis and Applications
- Solar-Powered Water Purification Methods
- Environmental remediation with nanomaterials
- Quantum Dots Synthesis And Properties
Universitat Autònoma de Barcelona
2008-2024
Imperial College London
2016-2021
Centre for Process Innovation
2021
Plastic Electronics (Netherlands)
2020
Transnational Press London
2018-2020
Kensington Health
2018-2019
Institut Català d'Investigació Química
2008-2018
Observatori de l'Ebre
2014-2016
Barcelona Institute for Science and Technology
2016
Institute of Science and Technology
2016
Oxygen vacancies are ubiquitous in metal oxides and critical to performance, yet the impact of these states upon charge carrier dynamics important for photoelectrochemical photocatalytic applications remains contentious poorly understood. A key challenge is unambiguous identification spectroscopic fingerprints which can be used track their function. Herein, we employ five complementary techniques modulate electronic occupancy associated with oxygen situ BiVO4 photoanodes, allowing us...
Abstract The effect of residual Pd on hydrogen evolution activity in conjugated polymer photocatalytic systems is systematically investigated using colloidal poly(9,9‐dioctylfluorene‐alt‐benzothiadiazole) (F8BT) nanoparticles as a model system. Residual Pd, originating from the synthesis F8BT via catalyzed polycondensation polymerization, observed form homogeneously distributed within polymer. essential for any to be this polymer, and very low concentrations (<40 ppm) are sufficient have...
Abstract Ni/Fe oxyhydroxides are the best performing Earth-abundant electrocatalysts for water oxidation. However, origin of their remarkable performance is not well understood. Herein, we employ spectroelectrochemical techniques to analyse kinetics oxidation on a series oxyhydroxide films: FeOOH, FeOOHNiOOH, and Ni(Fe)OOH (5% Fe). The concentrations reaction rates oxidised states accumulated during catalysis determined. found exhibit fastest but accumulates fewer states, resulting in...
A medium concentration of oxygen vacancies (V<sub>O</sub> ≈ 2%) is critical to the performance WO<sub>3</sub> photoanodes for solar water oxidation, enhancing charge separation and reducing recombination across all timescales examined.
Semiconducting polymers are versatile materials for solar energy conversion and have gained popularity as photocatalysts sunlight-driven hydrogen production. Organic often contain residual metal impurities such palladium (Pd) clusters that formed during the polymerization reaction, there is increasing evidence a catalytic role of in polymer photocatalysts. Using transient operando optical spectroscopy on nanoparticles F8BT, P3HT, dibenzo[b,d]thiophene sulfone homopolymer P10, we demonstrate...
The kinetics of photoelectrochemical (PEC) oxidation methanol, as a model organic substrate, on α-Fe2O3 photoanodes are studied using photoinduced absorption spectroscopy and transient photocurrent measurements. Methanol is oxidized to formaldehyde with near unity Faradaic efficiency. A rate law analysis under quasi-steady-state conditions PEC methanol indicates that reaction second order in the density surface holes hematite independent applied potential. Analogous data anatase TiO2...
The main objective of this review is to give a general overview the structure, electrochemistry (when available), and catalytic performance Ru complexes, which are capable oxidizing water molecular dioxygen, highlight their more relevant features. description catalysts mainly divided into complexes that contain Ru−O−Ru bridging group those do not. Finally few conclusions drawn from global all presented here, some guidelines for future catalyst design given.
A thorough understanding of the kinetic competition between desired water oxidation/electron extraction processes and any detrimental surface recombination is required to achieve high oxidation efficiencies in transition-metal oxide systems. The kinetics these Faradaic efficiency tungsten trioxide (WO3) photoanodes (>85%) are monitored herein by transient diffuse reflectance spectroscopy correlated with photocurrent data for electron extraction. Under anodic bias, efficient hole transfer...
Using WO<sub>3</sub> as a model material, we investigate how different oxygen vacancy concentrations affect trapping of photogenerated charges and photocatalytic reactions in metal oxides.
It has been more than 40 years since Fujishima and Honda demonstrated water splitting using TiO2, yet there is still no clear mechanism by which surface holes on TiO2 oxidize water. In this paper, we use a range of complementary techniques to study reaction that provide unique insight into the mechanism. Using transient photocurrent absorption spectroscopy, measure both kinetics electron extraction (t50% ≈ 200 μs, 1.5VRHE) hole oxidation 100 ms, as function applied potential, demonstrating...
Abstract Multi-electron heterogeneous catalysis is a pivotal element in the (photo)electrochemical generation of solar fuels. However, mechanistic studies these systems are difficult to elucidate by means electrochemical methods alone. Here we report spectroelectrochemical analysis hydrogen evolution on ruthenium oxide employed as an electrocatalyst and part cuprous oxide-based photocathode. We use optical absorbance spectroscopy quantify densities reduced species, correlate with current...
With the emergence of nonfullerene electron acceptors resulting in further breakthroughs performance organic solar cells, there is now an urgent need to understand their degradation mechanisms order improve intrinsic stability through better material design. In this study, we present quantitative evidence for a common root cause light-induced polymer:nonfullerene and polymer:fullerene cells air, namely, fast photo-oxidation process photoactive materials mediated by formation superoxide...
Spectroelectrochemical studies employing pulsed LED irradiation are used to investigate the kinetics of water oxidation on undoped dense bismuth vanadate (BiVO4) photoanodes under conditions photoelectrochemical and compare those obtained for a simple redox couple. These measurements employed determine quasi-steady-state densities surface-accumulated holes, ps, correlate these with photocurrent density as function light intensity, allowing rate law analysis mechanism. The reaction order in...
Unveiling the role of applied bias on charge carrier dynamics in WO<sub>3</sub>/BiVO<sub>4</sub> junction during water oxidation.
Electrochemical reduction of the dizaonium complex, [RuII(bda)(NO)(N–N2)2]3+, 23+ (N–N22+ is 4-(pyridin-4-yl) benzenediazonium and bda2– [2,2′-bipyridine]-6,6′-dicarboxylate), in acetone produces covalent grafting this molecular complex onto glassy carbon (GC) electrodes. Multiple cycling voltammetric experiments on GC electrode generates hybrid materials labeled as GC-4, with corresponding Ru-aqua anchored graphite surface. GC-4 has been characterized at pH = 7.0 by electrochemical...
Solar water splitting is a promising solution for the renewable production of hydrogen as an energy vector. To date, complex or patterned photoelectrodes have shown highest efficiencies, but lack scalable routes commercial scale-up. In this article, we report direct and chemical vapor deposition (CVD) route at atmospheric pressure, single step fabrication nanoneedle structured WO3 photoanodes. Using systematic approach, nanostructure was engineered to find conditions that result in optimal...
Catalyst modification of metal oxide photoanodes can result in markedly improved water oxidation efficiency. However, the reasons for improvement are often subtle and controversial. Upon depositing a CoFe Prussian blue (CoFe-PB) catalyst on BiVO4, large photocurrent increase onset potential shift (up to 0.8 V) observed, resulting substantially more efficient system with high stability. To elucidate origin this enhancement, we used time-resolved spectroscopies compare dynamics photogenerated...
Abstract Here, it is investigated whether an energetic cascade between mixed and pure regions assists in suppressing recombination losses non‐fullerene acceptor (NFA)‐based organic solar cells. The impact of polymer‐NFA blend composition upon morphology, energetics, charge carrier kinetics, photocurrent properties are studied. By changing film composition, morphological structures varied from consisting highly intermixed phases to both phase. Cyclic voltammetry employed investigate the...
Moving from hexagonal boron nitride (h-BN), a well-known crystalline insulator, to amorphous BN, leads the creation of semiconductor able photoreduce CO<sub>2</sub> in gas/solid phase, under UV-vis and pure visible light.
In metal oxide-based photoelectrochemical devices, the spatial separation of photogenerated electrons and holes is typically attributed to band-bending at oxide/electrolyte interface. However, direct evidence such impacting upon charge carrier lifetimes has been very limited date. Herein we use ultrafast spectroscopy track rapid relaxation in space-charge layer their recombination with trapped WO3 photoanodes. We observe that applied bias can significantly increase on all time scales from...
Elucidating the role of charge accumulation and reaction kinetics in governing performance Ni/Fe oxyhydroxides as electrocatalysts co-catalysts on BiVO<sub>4</sub> photoanodes water oxidation.
Abstract Analogously to enzymatic catalysis, where the active metal sites and their environment are controlled by protein residues, catalytic properties of nanoparticles (NPs) can be tuned carefully selecting surface‐coordinated species. In artificial photosynthesis, surface‐functionalization emerged in last decade, grounded on development reliable methods for tailored synthesis, advanced characterization theoretical modeling NPs, altogether with aim transferring nanoscale mechanistic...
The preparation of three new octadentate tetranucleating ligands made out two Ru-Hbpp-based units [where Hbpp is 3,5(bispyridyl)pyrazole], linked by a xylyl group attached at the pyrazolate moiety, general formula (Hbpp)(2)-u-xyl (u = p, m, or o) reported, together with its dinucleating counterpart substituted same position benzyl group, Hbpp-bz. All these have been characterized usual analytical and spectroscopic techniques. corresponding tetranuclear ruthenium complexes...