Solar-Driven Hydrogen Production: Recent Advances, Challenges, and Future Perspectives

Abstract

Solar H 2 production is considered as a potentially promising way to utilize solar energy and tackle climate change stemming from the combustion of fossil fuels. Photocatalytic, photoelectrochemical, photovoltaic−electrochemical, solar thermochemical, photothermal catalytic, and photobiological technologies are the most intensively studied routes for solar H 2 production. In this Focus Review, we provide a comprehensive review of these technologies. After a brief introduction of the principles and mechanisms of these technologies, the recent achievements in solar H 2 production are summarized, with a particular focus on the high solar-to-H 2 (STH) conversion efficiency achieved by each route. We then comparatively analyze and evaluate these technologies based on the metrics of STH efficiency, durability, economic viability, and environmental sustainability, aiming to assess the commercial feasibility of these solar technologies compared with current industrial H 2 production processes. Finally, the challenges and prospects of future research on solar H 2 production technologies are presented.

Molecular Hyperpolarization-Directed Photothermally Enhanced Melanin-Inspired Polymers

“…People are calling for the development of renewable energy technologies to reduce the pressure on our living environment and energy supply. − As an inexhaustible clean energy, solar energy has received widespread attention. − To efficiently convert solar energy into other kinds of usable energy, the design of conversion materials is the key issue, and increasing the light absorption capacity of materials is always highly desirable. − Constructing the donor–acceptor (D–A) conjugate structures is a common molecular design strategy in the field of organic optoelectronics. The chemical connection between strong acceptor and donor building blocks can significantly offer numerous types of D–A pairs, which would greatly change the polarizability and dipole moment of the local molecule structures and induce the re-hybridization of molecular orbitals. − Molecular orbital re-hybridization could further lead to the decrease of the lowest unoccupied molecular orbital (LUMO) as well as the increase of the highest occupied molecular orbital (HOMO) within the system, thereby reducing the molecular optical bandgap.…”

Physical Basis of Multi-Energy Coupling-Driven Water Oxidation

“…Maximizing the energy efficiency is a significant challenge in the case of multi-energy inputs, depending on the discovery of energy coupling mechanism. The photoelectrochemical catalysis is the well-known light–electricity coupling water splitting based on a semiconductor–liquid junction mechanism ( Song et al, 2022 ). In this system, the external electric field contributes to promoting photogenerated charge separation and extraction and the polarization of the catalytic layer to meet energy-level requirement of water oxidation.…”

Identifying Key Design Criteria for Large-Scale Photocatalytic Hydrogen Generation from Engineering and Economic Perspectives

“…With that the efficiency of photocatalytic H 2 production via water splitting (<5% solar-to-hydrogen efficiency) is yet to be compatible to these approaches. , On the basis of the prior studies which compared PV–EC, PEC, and photocatalysis, − the simplicity (PV–EC and PEC system constructions are more complex when compared to a photocatalytic system), low maintenance costs, and low electricity consumption (primary energy source is sunlight) demonstrate that the photocatalytic system still displays substantial advantages in terms of sustainable green H 2 production. Very recently, Song et al evaluated the commercial feasibility of several potential technologies for solar-driven H 2 generation (i.e., PV–EC, PEC, photocatalysis, and other catalysis) based on the solar-to-hydrogen efficiency, economic viability, durability, and sustainability . Their study highlighted that photocatalysis is the simplest system which could potentially deliver the lowest levelized H 2 cost.…”