Efficient Solar Water Splitting Photocathodes Comprising a Copper Oxide Heterostructure Protected by a Thin Carbon Layer

Abstract

Photoelectrochemical (PEC) solar water splitting has received extensive attention because it promises to provide an alternative and sustainable source of energy. A key challenge is to achieve a stable PEC system in either acidic or basic electrolyte without degradation of the (photo)­electrodes. We have used a cubic Cu2O film and porous granular bilayer Cu2O/CuO composite with a carbon protection layer as photocathode materials. The films were deposited under different conditions, such as variation of the electrodeposition time, thermal oxidation of the Cu2O films in air versus nitrogen atmosphere, and deposition of the carbon materials, and were investigated structurally and with regard to their PEC performance. The optimized electrodes showed photocurrents up to 6.5 and 7.5 mA/cm–2 at potentials of 0 and −0.1 V vs RHE at pH 5.5, respectively. The stabilities of the Cu2O/C and Cu2O/CuO/C photocathodes, at a low bias of 0.3 V vs RHE, were retained after 50 h. The strongly improved photostability of the photocathodes in comparison to electrodes in the absence of a carbon overlayer is attributed to a more effective charge transfer and a protective role of carbon against photocorrosion.

Arc Synthesis, Crystal Structure, and Photoelectrochemistry of Copper(I) Tungstate

“…This finding further supports thermal oxidation of Cu 2 WO 4 occurring via oxidation to CuWO 4 and expulsion of CuO from the compound framework ( eq 1 ), the latter being known to absorb light at wavelengths longer than 800 nm. 57 …”

Elucidating the Synergistic Behavior of Orientation‐Controlled SnS Nanoplates and Carbon Layers for High‐Performance Lithium‐ and Sodium‐Ion Batteries

“…During the annealing process, the glucose was dehydrated and covalently cross‐linked through aromatization and carbonization, resulting in uniform carbon layers on the SnS surface. [ 35–37 ] PL‐SnS@C was also prepared using the same carbon‐coating process. Top‐view SEM images (Figure S7a,b, Supporting Information) of the as‐prepared NSCs did not show any structural changes after the application of the carbon coating.…”

Solution-Processed Synthesis of Copper Oxide (CuxO) Thin Films for Efficient Photocatalytic Solar Water Splitting

“…The Cu x O photocathode annealed at 350 °C showed better stability against photocorrosion among the all synthesized Cu x O photoelectrodes. However, many researchers have already tried to overcome the stability issue of the Cu x O photocathodes through a successful way of using a surface protective layer on the Cu x O photocathodes. ,,,,, Following the same strategy, future research could be conducted to improve the stability of Cu x O photocathodes synthesized by the reduction of spin-coated CuI thin films.…”