Bias-free solar NH3 production by perovskite-based photocathode coupled to valorization of glycerol

Abstract

Photoelectrochemical production of ammonia (NH3) is potentially eco-friendly but suffers from a low solar-to-ammonia productivity (SAP) and requires a high additional bias for the overall NH3 production from nitrate reduction and water oxidation. Here we applied a high-performance triple-cation lead halide (Cs-0.05(FA(0.83)MA(0.17))(0.95)Pb(Br0.17I0.83)(3)) perovskite photocathode with integrated electrocatalyst to achieve high SAP and coupled glycerol oxidation instead of water oxidation for bias-free NH3 production. Stable, selective NH3 production and glycerol oxidation were achieved by respectively loading Ru and Pt electrocatalysts on conductive and stable titanate nanosheet supports, instead of corrodible carbon-based supports. Our photoelectrochemical NH3 production system coupled to glycerol oxidation demonstrated a photocurrent density of 21.2 +/- 0.7 mA cm(-2) and SAP of 1,744.9 +/- 20.6 mu g(NH3) cm(-)(2) h(-)(1) with 99.5 +/- 0.8% Faradaic efficiency without applying any additional bias. Simultaneously, glycerol was selectively oxidized to glyceric acid as a major value-added product.