Synthesis and Performance of Photocatalysts for Photocatalytic Hydrogen Production: Future Perspectives

Abstract

Photocatalysis for “green” hydrogen production is a technology of increasing importance that has been studied using both TiO2–based and heterojunction composite-based semiconductors. Different irradiation sources and reactor units can be considered for the enhancement of photocatalysis. Current approaches also consider the use of electron/hole scavengers, organic species, such as ethanol, that are “available” in agricultural waste, in communities around the world. Alternatively, organic pollutants present in wastewaters can be used as organic scavengers, reducing health and environmental concerns for plants, animals, and humans. Thus, photocatalysis may help reduce the carbon footprint of energy production by generating H2, a friendly energy carrier, and by minimizing water contamination. This review discusses the most up-to-date and important information on photocatalysis for hydrogen production, providing a critical evaluation of: (1) The synthesis and characterization of semiconductor materials; (2) The design of photocatalytic reactors; (3) The reaction engineering of photocatalysis; (4) Photocatalysis energy efficiencies; and (5) The future opportunities for photocatalysis using artificial intelligence. Overall, this review describes the state-of-the-art of TiO2–based and heterojunction composite-based semiconductors that produce H2 from aqueous systems, demonstrating the viability of photocatalysis for “green” hydrogen production.

Efficient CdS Nanoparticle/Zn(OH)F Heterojunction Catalysts for Hydrogen Evolution

“…Photocatalysis hydrogen production is now the cleanest and the most inexpensive technology . Semiconductor heterojunction photocatalysts, using visible light for hydrogen production, have the characteristics of low energy consumption and a wide range of applications. , Therefore, developing efficient, stable, and noble-metal-free heterojunction photocatalytic materials has become a hot research direction.…”

2023 roadmap on photocatalytic water splitting

“…To accomplish this, analytical instruments including GC-MS, HPLC, Raman spectroscopy should be adapted for the detection and quantification of organic scavenger derived chemical species. In addition, applicable reaction models are required for the establishment of reliable kinetics, consistent with postulated reaction mechanics [117,125]. These kinetic models should be studied and developed to lead to PC reactor operations with high QYs and PTEFs.…”

“…These reactors manage large ranges of temperatures, pressures, compositions, and pHs. Despite of these advancements, there are still challenges for hydrogen production in PC reactors including their ability to provide (a) homogeneous and uniform irradiation throughout the reactor volume, (b) high mixing of the semiconductor slurry, interacting efficiently with photons [117], and (c) high photon absorption promoting e − /h + pair formation. New designs should also include carefully selected (a) irradiation sources, (b) light source placement, and (c) photocatalyst state, either fixed or suspended [116].…”

“…The development of kinetic models requires experimental data describing the chemical species changes with irradiation time [117]. Furthermore, a good kinetic model should be based on applicable assumptions (i.e.…”

Preparation and photocatalytic hydrogen evolution performance of square platform Cu2MoS4/lamellar ZnIn2S4

“…Therefore, photocatalytic hydrogen evolution has attracted the attention of the scientific community in recent years, and the conversion of renewable solar energy into clean hydrogen energy is considered as a promising solution to the energy crisis. 1–5…”