Integrating Perovskite Photovoltaics and Noble-Metal-Free Catalysts toward Efficient Solar Energy Conversion and H2S Splitting

Hydrogen sulfide (H2S) has been considered as a potential hydrogen source. Identifying efficient solar-driven processes and low-cost materials that can extract hydrogen from H2S is highly attractive. Herein, for the first time, we reported the establishment of a perovskite photovoltaic-electrolysis (PV-EC) H2S splitting system by integrating a single perovskite solar cell, noble-metal-free catalysts, and H2S splitting reaction with the aid of mediators. The as-established system delivered a solar-to-chemical energy conversion efficiency of up to 13.5% during the PV-EC step by using molybdenum–tungsten phosphide (Mo–W–P) as the catalyst for a hydrogen evolution reaction (HER) and a graphite carbon sheet as the catalyst for the oxidation of mediators, respectively. To the best of our knowledge, this is among the highest value ever reported for the artificial conversion of solar to chemical energy using perovskite solar cells. Moreover, upon integration with the PV-EC system, a H2S splitting reaction with a net energy conversion efficiency of 3.5% can be accomplished, and the overall energy consumption to obtain an equivalent amount of H2 from H2S is reduced by ca. 43.3% compared with that from water splitting. This paradigm of producing value-added chemicals by consuming negative value waste products is solely based on low-cost materials and a simpler system configuration, which significantly improves the economic sustainability of the process.