Insights into the carbonate effect on water oxidation over metal oxide photocatalysts/photoanodes

Abstract

Photocatalytic/photoelectrochemical water splitting using metal oxide semiconductors is a promising technology for direct and simple solar-energy conversion. The addition of carbonate salts to an aqueous reaction solution has been known...

Selective Oxidation of Sulfuric Acid to Peroxydisulfuric Acid on a Tungsten Trioxide Anode

“…The Pople‐type split valence basis set of 6‐311+G(d,p) [23] was used for H, O, and S atoms, [24] whereas the Stuttgart/Dresden effective core potential basis set (SDD) was used for Sn and W atoms [25,26] . This approach provided appropriate geometries for isolated molecules that consisted of H, O, and S atoms (Figure S1), as well as W−O and Sn−O structures, [27,28] as reported previously [17,29–31] . Frequency calculations were performed to confirm optimized structures with no imaginary frequencies, which corresponded to the real minima on the entire potential energy surface.…”

“…[25,26] This approach provided appropriate geometries for isolated molecules that consisted of H, O, and S atoms (Figure S1), as well as WÀ O and SnÀ O structures, [27,28] as reported previously. [17,[29][30][31] Frequency calculations were performed to confirm optimized structures with no imaginary frequencies, which corresponded to the real minima on the entire potential energy surface. They were also conducted to determine zero-point vibrational energies.…”

“…Herein, we focused on the oxidation of H 2 SO 4 on metal oxides to form H 2 S 2 O 8 using quantum chemical calculations at a density functional theory (DFT) level. By applying a commonly accepted theoretical description that consisted of four protoncoupled electron transfer (PCET) steps with two H 2 O molecules to O 2 , [15][16][17] the two-electron oxidation mechanism of H 2 SO 4 and H 2 O on WO 3 , SnO 2 , and their interfaces were investigated using molecular cluster models. [15,16,18,19] We also conducted electrochemical experiments with WO 3 /FTO and FTO (SnO 2 ) anodes of the H 2 S 2 O 8 production in an aqueous H 2 SO 4 solution.…”

Discovery of LaAlO3 as an efficient catalyst for two-electron water electrolysis towards hydrogen peroxide

“…Additionally, we calculated the H 2 CO 3 oxidation mechanism proposed by Kusama et al (Supplementary Fig. 8 ) on the LaAlO 3 surface 51 . Our results agree well with the report by them and show that the first proton removal from the adsorbed H 2 CO 3 is the rate-limiting step.…”

Simultaneous production of hydrogen and chlorine through overall brine splitting with a particulate photocatalyst

“…The large dimensions of the photoelectrode (2 Â 3 cm 2 ) prevented the removal of Cl 2 gas from the surface, consequently promoting photolysis and Density functional theory (DFT) calculations were performed to scrutinize the kinetic aspects governing the selectivity for O 2 /HClO production. [24][25][26][27][28][29][30] Using a commonly accepted theoretical description involving four proton-coupled electron-transfer (PCET) steps with two H 2 O molecules, [31][32][33][34][35][36] the mechanisms underlying intermediate formation and oxidation of HCl and H 2 O were investigated using the Ti(OH) 2 -O 2 -Ti(OH) 2 cluster model for rutile TiO 2 . 34,35,37 The DFT results indicated that the first deprotonation step from the adsorbed HCl or H 2 O was the rate-limiting step for both reactions, similar to those reported previously for H 2 O oxidation (Fig.…”