RESUMEN
Despite having favorable energetics and tunable optoelectronic properties, utilization of BaTiO3 (BTO) for photocatalytic reactions is limited by its absorption only in the ultraviolet region. To address this challenge, BTO is doped with iridium (Ir) to induce visible light absorption. The visible light-induced photocatalytic H2 generation efficiency is enhanced by 2 orders of magnitude on selective conversion of the Ir valence state from Ir4+ to Ir3+. To understand such intriguing behavior, valence state-dependent changes in the optoelectronic, structural, and surface properties and electronic band structure are comprehensively investigated. The effect of electron occupancy change between Ir4+ (t2g5 eg0) and Ir3+ (t2g6 eg0) and their energetic positions within the band gap is found to significantly influence H2 generation. Besides this, converting Ir4+ to Ir3+ enhanced the photocathodic current and lowered the onset potential. Results aid in designing photocatalysts to efficiently use low-energy photons for enhancing solar H2 production in these emerging BTO-based photocatalysts. Collectively, the observations made in this work highlight the promising application of Ir3+:BTO in z-scheme photocatalysis.
RESUMEN
Sustainable valorization of industrial and solid wastes by utilizing them as feedstock to generate H2 via the photocatalytic reforming (PR) process holds great promise. It can also be an effective method to treat solid waste that otherwise would require tedious and expensive processes. This approach has the potential to offer energy solutions and form value-added chemicals. In this direction, developing photocatalysts and tuning their properties play an essential role in advancing the H2 generation efficiency. This Review article explores the application of 2D photocatalysts to generate H2 via PR of industrial waste (H2S) and solid waste, such as plastic and biomass. Despite having favorable optoelectronic properties, 2D photocatalysts are not widely employed for the PR process. The latest progress in employing 2D photocatalysts to realize efficient H2 evolution from biomass, plastic, and industrial waste such as H2S is detailed in this Review. A correlation between the properties of 2D photocatalysts with H2 evolution rate is discussed. We also emphasize understanding the mechanism involved in the PR process and the importance of 2D photocatalysts design. Such rational insight aids in further enhancing the H2 generation efficiency by effectively using solid/industrial waste as a feedstock.
