Composition-Dependent Functionality of Copper Vanadate Photoanodes

Abstract

To understand functional roles of constituent elements in ternary metal oxide photoanodes, essential photoelectrochemical (PEC) properties are systematically analyzed on a series of copper vanadate compounds with different Cu:V elemental ratios. Homogeneous and highly continuous thin films of β-CuVO, γ-CuVO, CuVO, and CuVO are grown via reactive co-sputtering and their performance characteristics for the light-driven oxygen evolution reaction are evaluated. All four compounds have similar bandgaps in the range of 1.83-2.03 eV, though Cu-rich phases exhibit stronger optical absorption and higher charge separation efficiencies. Transient photocurrent analysis reveals a reduction of surface catalytic activity with increasing Cu:V elemental ratio due to competitive charge recombination at Cu-related surface states. This comprehensive analysis of PEC functionalities-including photon absorption, carrier separation, and heterogeneous charge transfer-informs strategies for improving PEC activity in the copper vanadate materials system and provides insights that may aid discovery, design, and engineering of new photoelectrode materials.

Deep eutectic solvent route synthesis of zinc and copper vanadate n-type semiconductors – mapping oxygen vacancies and their effect on photovoltage

“…18,19 Recently, copper vanadates were reported to be a potential photoanode candidate for the visible-light driven water splitting reaction. [20][21][22][23][24] In the electronic structure of b-Cu 2 V 2 O 7 the valence band maximum (VBM) and conduction band minimum (CBM) are dominated by O 2p and Cu 3d orbitals respectively. 22 The partially lled d-subshell of copper improves visible light absorption and photocurrent for the oxygen evolution reaction.…”

“…22 The partially lled d-subshell of copper improves visible light absorption and photocurrent for the oxygen evolution reaction. [20][21][22][23] Interestingly, a-Zn 2 V 2 O 7 and b-Cu 2 V 2 O 7 belong to the family of M 2 V 2 O 7 (M ¼ Zn and Cu) with similar monoclinic structures. Both compounds also resemble each other in that they have O 2p as the main contribution to the valence band maximum (VBM).…”

Successes and Opportunities for Discovery of Metal Oxide Photoanodes for Solar Fuels Generators

“…17 The breadth of these materials development strategies far exceeds the breadth of candidate photoanodes for which they have been deployed. The general bias in scientific research towards continued investigation of well-researched materials is both broadly known and recently evaluated as a limitation on creativity and discovery, 18 21 and computational investigation of β-Cu 2 V 2 O 7 22 to elucidate performance-limiting properties. Of these, only the copper vanadates exhibit a photon energy onset of photoactivity near 2 eV, the desired upper-limit described above.…”

Combinatorial screening yields discovery of 29 metal oxide photoanodes for solar fuel generation

“…[2][3][4] In addition to historic efforts in developing the binary oxides α-Fe2O3, TiO2 and WO3 as solar fuels photoanodes, there have been concerted efforts to both explore modes of optimization and understand limiting factors for ternary oxides, most notably BiVO4 2 and also ZnFe2O4, 5 α-SnWO4, 6 and copper vanadates. 7 HiTp experimental screening of OER photoanodes, pioneered by Parkinson 8,9 and McFarland 10 and advanced by others, [11][12][13] has accelerated exploration of photoanode candidates. The HiTp techniques described in the present work were previously deployed under guidance from first principles density functional theory (DFT) calculations, resulting in the discovery of β-Mn2V2O7 14 followed by 8 additional ternary metal vanadates 15,16 and 5 additional ternary metal manganates.…”