Calcium hydroxyphosphate, Ca₁₀(PO₄)₆(OH)₂, is commonly known as hydroxyapatite (HAP). The acidic calcium and basic phosphate/hydroxide sites in HAP can be modified via isomorphous substitution of calcium and/or hydroxide ions to enable a cornucopia of catalyzed reactions. Herein, isomorphic substitution of Ca²⁺ ions by Cu²⁺ ions especially at very low levels of exchange created new analogs of molecular surface frustrated Lewis pairs (SFLPs) in Cu_xCa_10−x(PO₄)₆(OH)₂, thereby boosting its performance metrics in heterogeneous CO₂ photocatalytic hydrogenation. In situ Fourier transform infrared spectroscopy characterization and density functional theory calculations provided fundamental insights into the catalytically active SFLPs defined as proximal Lewis acidic Cu²⁺ and Lewis basic OH⁻. The photocatalytic pathway proceeds through a formate reaction intermediate, which is generated by the reaction of CO₂ with heterolytically dissociated H₂ on the SFLPs. Given the wealth of information thus uncovered, it is highly likely that this work will spur the further development of similar classes of materials, leading to the advancement and, ultimately, large-scale application of photocatalytic CO₂ reduction technologies.

中文翻译：

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新活性位点的构建：用于 CO2 加氢的羟基磷灰石钙表面上的 Cu 取代使表面受阻路易斯对

羟基磷酸钙，Ca ₁₀ (PO ₄ ) ₆ (OH) ₂，通常被称为羟基磷灰石（HAP）。HAP 中的酸性钙和碱性磷酸盐/氢氧化物位点可以通过钙和/或氢氧根离子的同晶取代进行修饰，以实现催化反应的聚宝盆。在此，Ca ²⁺离子被Cu ²⁺离子同构取代，特别是在非常低的交换水平下，在Cu _x Ca _{10- x} (PO ₄ ) ₆ (OH) _{2 中}产生了分子表面受挫路易斯对（SFLP）的新类似物，从而提高其在异质 CO _{2 中的}性能指标光催化加氢。原位傅立叶变换红外光谱表征和密度泛函理论计算提供了对催化活性 SFLP 的基本见解，定义为近端路易斯酸性 Cu ²⁺和路易斯碱性 OH ^-。光催化途径通过甲酸反应中间体进行，甲酸反应中间体是由 CO ₂与SFLP 上异解离解的 H ₂反应产生的。鉴于由此发现的大量信息，这项工作很可能会刺激类似类别材料的进一步发展，从而推动光催化 CO ₂还原技术的进步并最终大规模应用。