Solar-driven co-production of H₂ and lactic acid from lignocellulose via Pt–C₃N₄ catalyst

Lignocellulose, the most abundant renewable biomass on Earth, offers great potential as a green hydrogen source and chemical feedstock, yet its efficient valorization continues to present scientific challenges. Recently, a team led by Prof. Zupeng Chen at Nanjing Forestry University developed a photocatalytic system of single-atom platinum on carbon nitride, presenting a solar-driven strategy for co-producing hydrogen and lactic acid. The study, published in Journal of Catalysis (10.1016/S1872-2067(25)64698-5), provides an eco-friendly strategy for biomass utilization.

The Pt–C₃N₄ catalyst was synthesized via a supramolecular self-assembly approach followed by a two-step calcination process, yielding atomically dispersed Pt sites uniformly anchored within a layered C₃N₄ framework. Structural characterizations confirmed that Pt atoms are stably coordinated with nitrogen atoms in the matrix, forming well-defined Pt–N bonds. This atomic dispersion endows the catalyst with superior electronic properties and stability compared to conventional Pt nanoparticles or clusters.

Under alkaline conditions (pH > 13) and 427 nm LED illumination, the optimized Pt–C₃N₄ catalyst achieved a hydrogen production rate of 6.34 mmol·mol⁻¹(Pt)·h⁻¹, which is 4.6 times higher than that of conventional Pt nanoparticle catalysts. In parallel, efficient lactic acid production was demonstrated from various monosaccharides including glucose, fructose, and xylose, with high conversion yields of 84.7%, 93.1%, and 96.5%, respectively.

Mechanistic investigations revealed a dual-pathway process involving photogenerated reactive oxygen species. Specifically, hydroxyl radicals (•OH) facilitated the oxidative cleavage of biomass into lactic acid via retro-aldol fragmentation and keto–enol tautomerization, while photoexcited electrons from the C₃N₄ scaffold reduced protons to generate H₂. Complementary theoretical simulations illustrated that the atomically dispersed Pt sites promoted spatial charge separation by localizing holes at Pt atoms and electrons on the C₃N₄ framework, thereby extending carrier lifetimes and enhancing overall photocatalytic efficiency.

This work not only demonstrates the effectiveness of single-atom photocatalysts in biomass photoreforming but also provides a scalable and sustainable system for simultaneous clean energy and chemical production from plant-derived waste under mild, solar-driven conditions.

About the Journal

Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 17.7. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

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