Photoelectrochemical oxidation

About: Photoelectrochemical oxidation is a research topic. Over the lifetime, 311 publications have been published within this topic receiving 34967 citations.

Electrochemical Photolysis of Water at a Semiconductor Electrode

Abstract: ALTHOUGH the possibility of water photolysis has been investigated by many workers, a useful method has only now been developed. Because water is transparent to visible light it cannot be decomposed directly, but only by radiation with wavelengths shorter than 190 nm (ref. 1).

Electrochemical and photoelectrochemical investigation of single-crystal anatase

Abstract: Single crystals of TiO2 anatase containing 0.22% of Al and traces of V, Zr, Nb, and La were grown by chemical transport reactions employing TeCl4 as the transporting agent. Electrodes having the (101) face exposed doped by reduction with hydrogen were employed. The electrochemical and photoelectrochemical behavior of a single crystal of anatase were scrutinized for the first time. Properties were compared to those of single-crystal rutile having the (001) face exposed. Impedance analysis established that the flatband potential of anatase (101) is shifted negatively by 0.2 V with regards to that of rutile (001). Interfacial capacitance measurements under forward bias indicate smaller density of surface states on anatase. Photoelectrochemical oxidation of water occurs on both rutile and anatase with incident photon-to-current conversion efficiencies close to unity at λ = 300 nm. From the comparison of Ufb and Eg, it follows that anatase (101) and rutile (001) electrodes differ mainly in the position of the ...

Probing the photoelectrochemical properties of hematite (α-Fe2O3) electrodes using hydrogen peroxide as a hole scavenger

Abstract: We study hematite (α-Fe2O3) photoelectrodes for water splitting by examining the fate of photogenerated holes. Using H2O2 as an efficient hole scavenger, we collect all holes that arrive at the electrode/electrolyte interface. This provides the ability to distinguish between and quantify bulk and surface recombination processes involved in the photoelectrochemical oxidation of water. Below 1.0 VRHE, electrolyte oxidation kinetics limits the performance but above 1.2 VRHE bulk recombination becomes the limiting factor.

Understanding the role of underlayers and overlayers in thin film hematite photoanodes

Abstract: Recent research on photoanodes for photoelectrochemical water splitting has introduced the concept of under- and overlayers for the activation of ultrathin hematite films. Their effects on the photocatalytic behavior were clearly shown; however, the mechanism is thus far not fully understood. Herein, the contribution of each layer is analyzed by means of electrochemical impedance spectroscopy, with the aim of obtaining a general understanding of surface and interface modifications and their influence on the hematite photoanode performance. This study shows that doping of the hematite from the underlayer and surface passivation from annealing treatments and an overlayer are key parameters to consider for the design of more efficient iron oxide electrodes. Understanding the contribution of these layers, a new design for ultrathin hematite films employing a combination of a gallium oxide overlayer with thin niobium oxide and silicon oxide underlayers is shown to achieve a photocurrent onset potential for the photoelectrochemical oxidation of water more negative than 750 mV versus the reversible hydrogen electrode (RHE) at pH 13.6, utilizing Co-Pi as a water oxidation catalyst. It is demonstrated that multilayer hematite thin film photoanodes are a strategy to reduce the overpotential for this material, thereby facilitating more efficient tandem cells.

Photoelectrochemical Oxidation of Water at Transparent Ferric Oxide Film Electrodes

Abstract: The fabrication of thin-film Fe2O3 photoanodes from the spray pyrolysis of Fe(III)-containing solutions is reported along with their structural characterization and application to the photoelectrolysis of water These films combine good performance, measured in terms of photocurrent density, with excellent mechanical stability A full investigation into the effects that modifications of the spray-pyrolysis method, such as the addition of dopants or structure-directing agents and changes in precursor species or carrier solvent, have on the performance of the photoanodes has been realized The largest photocurrents were obtained from photoanodes prepared from ferric chloride precursor solutions, simultaneously doped with Ti4+ (5%) and Al3+ (1%) Doping with Zn2+ also shows promise, cathodically shifting the onset potential by ∼022 V