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We report a facile synthesis of carbon quantum dot (CQD)-sensitized TiO 2 /Pt nanocomposites as efficient and robust photocatalysts for light-driven proton reduction from water. We show that this method not only simplifies the synthetic procedure for such hybrid materials but also enhances the direct interaction between CQDs and TiO 2 , which facilitates charge transfer from CQDs to TiO 2 and eventually improves its performance for light-driven H 2 generation. To the best of our knowledge, this work represents the system with highest H 2 generation efficiency among all CQD-sensitized materials.

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The traditional synthesis for bimetallic-based electrocatalysts is challengeable for fine composition and elemental distribution because of the uncontrollable growth speed of nanostructures utilizing metal salt precursors. Herein, a unique electrochemical corrosion engineering strategy is developed via electrochemically transforming metal solid substrates (iron foil and nickel foam) into a highly active Ni− Fe oxide film for oxygen evolution, rather than directly utilizing metal ion precursors. This synthesis involves electrochemical corrosion of a Fe foil in an aqueous electrolyte along with electrochemical passivation of Ni foam (NF). The released trace Fe ions gradually incorporate into passivated NF surfaces to construct Ni−Fe oxide film and crucially improve composition distribution in the catalyst film. As a result, the resulted film with an ultralow mass loading (0.22 mg cm −2 ) delivers large current densities of 500 mA cm −2 at overpotential of only 270 mV in 6.0 M KOH at 60 °C, outperforming many reported NiFe catalysts requiring much higher mass loadings. More interestingly, the as-prepared catalyst almost reaches the standard (500 mA cm −2 within the overpotential of 300 mV) in commercial water electrolysis with long-term stability for at least 10 h. This work may provide a unique synthesis strategy for nonprecious transition-metal catalysts for desirable water splitting and can be expanded to many other electrocatalysis systems.