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Fe–N–C materials exhibit excellent activity and stability for oxygen reduction reaction (ORR), as one of the most promising candidates to replace commercial Pt/C catalysts. However, it is challenging to unravel features of the superior ORR activity originating from Fe–N–C materials. In this work, the electronic and geometric structures of the isolated Fe–N–C sites and their correlations with the ORR performance are investigated by varying the secondary thermal activation temperature of a rationally designed NC‐supported Fe single‐atom catalyst (SAC). The systematic analyses demonstrate the significant role of coordinated atoms of SA and metallic Fe nanoparticles (NPs) in altering the electronic structure of isolated Fe–N–C sites. Meanwhile, strong interaction between isolated Fe–N–C sites and adjacent Fe NPs can change the geometric structure of isolated Fe–N–C sites. Theoretical calculations reveal that optimal regulation of the electronic and geometric structure of isolated Fe–N–C sites by the co‐existence of Fe NPs narrows the energy barriers of the rate‐limiting steps of ORR, resulting in outstanding ORR performance. This work not only provides the fundamental understanding of the underlying structure–activity relationship, but also sheds light on designing efficient Fe–N–C catalysts.

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This article describes how hydrogenation-induced surface disorder synergistically couples with the slow photon effect of TiO 2 photonic crystal to enhance solar light harvesting and charge separation efficiency, which results in a high performance toward photocatalytic hydrogen evolution.

Black TiO 2 obtained by hydrogenation has attracted enormous attention due to its unusual photocatalytic activity. In this contribution, a novel photocatalyst containing both a titanate−anatase heterostructure and a surface disordered shell was in situ synthesized by using a one-step hydrogenation treatment of titanate nanowires at ambient pressure, which exhibited remarkably improved photocatalytic activity for water splitting under simulated solar light. The as-hydrogenated catalyst with a heterostructure and a surface disordered shell displayed a high hydrogen production rate of 216.5 μmol·h −1 , which is ∼20 times higher than the Ptloaded titanate nanowires lacking of such unique structure. The in situgenerated heterostructure and hydrogenation-induced surface disorder can efficiently promote the separation and transfer of photoexcited electron−hole pairs, inhibiting the fast recombination of the generated charge carriers. A general synergistic effect of the heterostructure and the surface disordered shell on photocatalytic water splitting is revealed for the first time in this work, and the as-proposed photocatalyst design and preparation strategy could be widely extended to other composite photocatalytic systems used for solar energy conversion.

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Hydrogenation of semiconductors is an efficient way to increase their photocatalytic activity by forming disorder-engineered structures. Herein, we report a facile hydrogenation process of TiO2(B) nanobelts to in situ generate TiO2(B)-anatase heterophase junction with a disordered surface shell. The catalyst exhibits an excellent performance for photocatalytic hydrogen evolution under the simulated solar light irradiation (∼580 μmol h(-1), 0.02 g photocatalyst). The atomically well-matched heterophase junction, along with the disorder-engineered surface shell, promotes the separation of electron-hole and inhibits their recombination. This strategy can be further employed to design other disorder-engineered composite photocatalysts for solar energy utilization.