Precisely designing the atomic coordination structure of the catalytic center is highly desired to lower the energy barrier of CO₂ photoreduction. The present work shows that engineering Nb single atom coupled Bi–O vacancy pairs (V_Bi–O) into Bi₂₄O₃₁Br₁₀ (BOB) atomic layers can create a preferential local asymmetric structure. This configuration can result in a stronger local polarization electric field and thus prolong the carrier lifetime, as proved by ultrafast transient absorption spectroscopy. Meantime, this unique Nb SA-V_Bi–O associate favors the formation of strong chemical interaction between key *COOH intermediate and catalytic center, thus lowering the energy barrier of the rate-limiting step. Benefiting from these features, a high CO generation rate of 76.4 μmol g^–1 h^–1 for CO₂ photoreduction can be achieved over Nb SA-V_Bi–O BOB atomic layers in pure water, roughly 5.4 and 92.7 times higher than those of BOB atomic layers or bulk BOB, respectively. This work discloses an important paradigm for designing single atom coupled defect associates to optimize photocatalysis performance.

中文翻译：

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Nb 单原子耦合 Bi-O 空位对的不对称关联构型促进 CO2 光还原


精确设计催化中心的原子配位结构是降低 CO₂ 光还原的能垒的迫切希望。本工作表明，将 Nb 单原子耦合的 Bi-O 空位对 （V_Bi-O） 设计成 Bi₂₄O₃₁Br₁₀ （BOB） 原子层可以产生优先的局部不对称结构。这种配置可以产生更强的局部极化电场，从而延长载流子寿命，超快瞬态吸收光谱证明了这一点。同时，这种独特的 Nb SA-V_Bi-O 伴生剂有利于在关键的 *COOH 中间体和催化中心之间形成强化学相互作用，从而降低限速步骤的能垒。得益于这些特性，在纯水中的 Nb SA-V_Bi-O BOB 原子层上可以实现 76.4 μmol ^{g-1 h-1} 的高 CO_{2 光还原}率，分别比 BOB 原子层或体 BOB 高 5.4 倍和 92.7 倍。这项工作揭示了设计单原子耦合缺陷缔结物以优化光催化性能的重要范式。