Closed Loop Multi-Objective Optimization for Cu-Sb-S Photoelectrocatalytic Materials Discovery.

Copper antimony sulphides are regarded as promising catalysts for photoelectrochemical water splitting because of their earth abundance and broad light absorption. The unique photoactivity of copper antimony sulphides is dependent on their various crystalline structures and atomic compositions. Here, we built a closed-loop workflow that explores Cu-Sb-S compositional space to optimise its photoelectrocatalytic hydrogen evolution from water, by integrating a high-throughput robotic platform, characterization techniques, and machine learning (ML) optimization workflow. The multiple-objective optimization model discovered optimum experimental conditions after only nine cycles of integrated experiments-machine learning loop. Photocurrent testing at 0 V versus reversible hydrogen electrode (RHE) confirmed the expected correlation between the materials properties and photocurrent. An optimum photocurrent of -186 µA cm -2 was observed on Cu-Sb-S in the ratio of 9:45:46 in the form of single-layer coating on F-doped SnO 2 (FTO) glass with a corresponding bandgap of 1.85 eV and 63.2% Cu 1+ /Cu species content. The targeted intelligent search revealed a non-obvious CuSbS composition that exhibited 2.3 times greater activity than baseline results from random sampling. This article is protected by copyright. All rights reserved.