Developing efficient photocatalysts for synchronously producing H2 and high value‐added chemicals holds great promise to enhance solar energy conversion. Herein, a facile strategy of simultaneously engineering Pd cocatalyst and oxygen vacancies (VOs) on TiO2 to promote H2 production coupled with selective oxidation of benzylamine is demonstrated. The optimized PdSA+C/TiO2‐VO photocatalyst containing Pd single atoms (SAs), clusters (C), and VOs exhibits much superior performance to those of TiO2‐VO and PdSA/TiO2‐VO counterparts. The production rates of H2 and N‐benzylidenebenzylamine over PdSA+C/TiO2‐VO are 52.7 and 1.5 times those over TiO2‐VO, respectively. Both experimental and theoretical studies have elucidated the synergistic effect of Pd SAs, clusters, and VOs on TiO2 in boosting the photocatalytic reaction. The presence of Pd SAs facilitates the generation and stabilization of abundant VOs by the formation of PdOTi3+ atomic interface, while Pd clusters promote the photogenerated charge separation and afford the optimum active sites for H2 evolution. Surface VOs of TiO2 guarantee the efficient adsorption and dissociation/activation of reactant molecules. This study reveals the effect of active‐site engineering on the photocatalysis and is expected to shed substantial light on future structure design and modulation of semiconductor photocatalysts.

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Single‐atom (SA) catalysis bridging homogeneous and heterogeneous catalysis offers new opportunities for organic synthesis, but developing SA catalysts with high activity and stability is still a great challenge. Herein, a heterogeneous catalyst of Pd SAs anchored in 3D ordered macroporous ceria (Pd‐SAs/3DOM‐CeO2) is developed through a facile template‐assisted pyrolysis method. The high specific surface area of 3DOM CeO2 facilitates the heavily anchoring of Pd SAs, while the introduction of Pd atoms induces the generation of surface oxygen vacancies and prevents the grain growth of CeO2 support. The Pd‐SAs/3DOM‐CeO2 catalyst exhibits excellent activity toward Suzuki coupling reactions for a broad scope of substrates under ambient conditions, and the Pd SAs can be stabilized in CeO2 in long‐term catalytic cycles without leaching or aggregating. Theoretical calculations indicate that the CeO2 supported Pd SAs can remarkably reduce the energy barriers of both transmetalation and reductive elimination steps for Suzuki coupling reactions. The strong metal‐support interaction contributes to modulating the electronic state and maintaining the stability of Pd SA sites. This work demonstrates an effective strategy to design and synthesize stable single‐atom catalysts as well as sheds new light on the origin for enhanced catalysis based on the strong metal‐support interactions.