New Iron‐Cobalt Oxide Catalysts Promoting BiVO₄ Films for Photoelectrochemical Water Splitting

Abstract

Owing to the sluggish kinetics for water oxidation, severe surface charge recombination is a major energy loss that hinders efficient photoelectrochemical (PEC) water splitting. Herein, a simple process is developed for preparing a new type of low-cost iron-cobalt oxide (FeCoO x ) as an efficient co-catalyst to suppress the surface charge recombination on bismuth vanadate (BiVO 4 ) photoanodes. The new FeCoO x /BiVO 4 photoanode exhibits a high photocurrent density of 4.82 mA cm −2 at 1.23 V versus the reversible hydrogen electrode under AM 1.5 G illumination, which corresponds to >100% increase compared to that of the pristine BiVO 4 photoanode. The photoanode also demonstrates a high charge separation efficiency of ≈90% with excellent stability of over 10 h, indicating the excellent catalytic performance of FeCoO x in the PEC process. Density functional theory calculations and experimental studies reveal that the incorporation of Fe into CoO x generates abundant oxygen vacancies and forms a p-n heterojunction with BiVO 4 , which effectively promotes the hole transport/trapping from the BiVO 4 photocatalyst and reduces the overpotential for oxygen evolution reaction (OER), resulting in remarkably increased photocurrent densities and durability. This work demonstrates a feasible process for depositing cheap FeCoO x as an excellent OER cocatalyst on photoanodes for PEC water splitting.

Perovskite Oxide Based Electrodes for High‐Performance Photoelectrochemical Water Splitting

“…Thed evelopment and design of active and durable PEC water splitting systems have attracted considerably more attention in the past decade. [24][25][26][27][28] In particular,p hotoelectrodes are key to the PEC water splitting devices,which harvest sunlight to produce electron-hole pairs with subsequent separation and transportation processes.M etal oxides,s ulfides,a nd nitrides are promising photoelectrodes in PEC water splitting, [29][30][31][32][33][34] among which metal oxides including TiO 2 ,Z nO,S nO 2 ,F e 2 O 3 ,a nd WO 3 are predominantly explored due to their low cost, suitable semiconducting properties,s uperior stability,a bundance and easy nanostructuring capability. [35][36][37][38][39][40] According to the working principles of PEC water splitting,p hotoelectrodes,e specially the photoanode,s hould have both high electrocatalytic activity and sunlight absorption capability to achieve high STH efficiency, which cannot be easily obtained by simple metal oxides due to the fixed atomic environment.…”

Boosting the Performance of BiVO4 Prepared through Alkaline Electrodeposition with an Amorphous Fe Co‐Catalyst

“…Among these methods, BiVO 4 doping, photocharging, cathodic polarization, nanostructuring,, as well as its interfacing with: highly active OER co‐catalysts ( cocats ) another SC and plasmonic materials, have shown great promise. The synthesis of photoelectrochemically active BiVO 4 on a conductive substrate is thus of great importance and can be performed by: i ) spray‐based,,, or ii ) hydrothermal, methods, iii ) metal‐organic decomposition,,, iv ) physical vapor deposition, and v ) electrodeposition ,. The latter approach is very attractive due to its simplicity and its low cost, and electrodeposited BiVO 4 has already led to very important breakthroughs ,.…”

Ion Sputtering–Assisted Double‐Side Interfacial Engineering for CdIn2S4 Photoanode toward Improved Photoelectrochemical Water Splitting

“…Photoelectrochemical (PEC) water splitting provides a practical route to produce hydrogen by exploiting unlimited solar energy. [1,2] Given that four-electron-involved water oxidation is the rate-limiting step in the overall water splitting, the exploration of highly efficient photoanodes for oxygen evolution reaction (OER) has attracted extensive attention. [3][4][5] The desirable photoanode materials should satisfy the requirements of sufficient light harvesting, effective charge separation and transport, and ideal surface OER dynamics.…”