太阳能光催化分解水制氢以其系统简单、成本低廉的优势,成为解决当前能源与环境问题、实现“双碳”目标的理想途径之一。然而,传统研究多聚焦于光催化材料本身,对反应界面(涉及气、液、固三相)能量和物质传输转换机制缺乏系统的跨尺度考量,致使整体光−氢转化效率长期处于较低水平。研究从能质传输与转化的角度出发,概述了光催化分解水制氢的基本原理和过程,并深入探讨了非稳态光吸收吸收与能量转化、缓慢的传质过程(特别是反应界面气泡成核、生长和脱附过程)以及极端地区水资源匮乏等瓶颈问题。针对这些挑战,提出了若干突破途径。首先,重点介绍了一种太阳能聚光−光热耦合反应系统,通过聚光技术实现光热协同,显著提高了太阳能的宽光谱利用率以及载流子的反应势能和转化效率。其次,详细论述了基于光热基底构建全新的液−固/气−固解耦型反应体系的理论和方法,有效克服三相体系中因气泡生成造成的传质限制。再次,阐述了利用太阳能分频技术和气固界面构建,实现空气集水与光催化分解水耦合制氢的策略,以应对水资源受限问题。最后,从工程化角度强调了系统设计及其规模示范的深远影响和重要意义,并对这一领域未来的研究方向提出了展望。

Solar photocatalytic water splitting for H2 production, with a simple and cost-effective reaction system, holds significantpromise for addressing the current energy and environmental crises while achieving the “dual carbon” goals. However,traditionalstudies have primarily centered on the design of photocatalytic materials,lacking a systematic and cross-scale understanding of the energyand mass transfer and conversion processes at the reaction interface (involving gas, liquid, and solid phases). This oversight hasresulted in low solar-to-H2 efficiency. This review elucidates the basic principle and processes of photocatalytic water splitting from theperspective of energy and mass flow,and delves into the bottlenecks,including non-steady-state light absorption and energy conversion,slow mass transfer processes (especially the nucleation,growth,and detachment of reaction interface bubbles,and the scarcity of water resources in extreme regions. In response to these challenges, this review elaborates on several breakthrough approaches. Firstly, itintroduces a solar concentrating-photothermal coupling reaction system,which significantly enhances the wide-spectrum utilization ofsolar energy and the reaction potential and conversion efficiency of photogenerated carriers by utilizing concentrated photothermaltechnology to synergize light and heat. Secondly,this review elaborates on the theoretical and methodological foundations for constructinga new liquid-solid/gas-solid decoupled reaction system based on photothermal substrate, effectively overcoming the mass transferlimitations caused by bubble formation in traditional three-phase systems. Thirdly,it discusses the strategy for hydrogen production bycoupling with atmospheric water harvesting and photocatalytic water splitting to address water scarcity issues,utilizing solar frequency-division technology and gas-solid interface construction. Finally,from an engineering perspective,it emphasizes the significant impact andimportance of system design and large-scale demonstration,and proposes future research directions in this field.