Double Perovskite Cobaltites Integrated in a Monolithic and Noble Metal-Free Photoelectrochemical Device for Efficient Water Splitting.

Junjie Zhu,Halvard Haug,Athanasios Chatzitakis,Jónína B Guđmundsdóttir,Thomas Aarholt,Ragnar Strandbakke,Ingvild J T Jensen,Truls Norby,Magnus H Sørby,Matylda N Guzik,Patricia A Carvalho,Kevin G Both

doi:10.1021/acsami.1c01900

Abstract

Water photoelectrolysis has the potential to produce renewable hydrogen fuel, therefore addressing the intermittent nature of sunlight. Herein, a monolithic, photovoltaic (PV)-assisted water electrolysis device of minimal engineering and of low (in the μg range) noble-metal-free catalysts loading is presented for unassisted water splitting in alkaline media. An efficient double perovskite cobaltite catalyst, originally developed for high-temperature proton-conducting ceramic electrolyzers, possesses high activity for the oxygen evolution reaction in alkaline media at room temperatures too. Ba1–xGd1–yLax+yCo2O6−δ (BGLC) is combined with a NiMo cathode, and a solar-to-hydrogen efficiency of 6.6% in 1.0 M NaOH, under 1 sun simulated illumination for 71 h, is demonstrated. This work highlights how readily available earth-abundant materials and established PV methods can achieve high performance and stable and monolithic photoelectrolysis devices with potential for full-scale applications.

Highlights

Photoelectrochemical (PEC) water splitting is categorized among the six most promising pathways for the production of renewable hydrogen gas.[1]
The anode of our ea-PV− PEC device was based on a new class of double perovskite cobaltites for the oxygen evolution reaction (OER) of the general formula Ba1−xGd1−yLax+yCo2O6−δ (BGLC) and showed high catalytic activity, reporting a 6.6% STH under 71 h of continuous illumination
HRSTEM high-angle annular dark field (HAADF) imaging of BGLC587, which was the best performing among the presented double perovskites, revealed an A-site order-to-disorder transition from preto postoperation that did not affect the catalytic activity for the OER

Summary

Introduction

Photoelectrochemical (PEC) water splitting is categorized among the six most promising pathways for the production of renewable hydrogen gas.[1]. Immense efforts have since been devoted to the electrolysis and photoelectrolysis of water with the key challenges still found for the complex four-electron oxygen evolution reaction (OER) and the stability of the (photoelectro)catalysts.[10−12] the scarcity of certain highly efficient catalyst elements, such as Ir and Ru, renders photoelectrolysis of water nonviable so far. Oxide perovskites (ABO3) have shown high efficiency and stability for the OER in alkaline water electrolysis.[14−17] The increasing interest in oxide perovskites stems from their chemical stability, as well as their structural, compositional, and electronic versatility.[18−20]

Results

Discussion

Conclusion