Constructing asymmetric dual active sites is an effective strategy to promote formation of the C₂ product in photocatalytic CO₂ reactions, attributed to the suppressed dipole–dipole repulsion facilitating C–C coupling. However, information about the extent of asymmetry is still absent, making the precise design of asymmetric sites a challenge. Herein, Bader charge variation (Δq) in intermetallics was chosen as the descriptor to select asymmetric sites, where a linear relation between Δq and the adsorption energy of the C₂ intermediate is found. From 66 intermetallic candidates, FePt stood out, with Δq = 0.503 e^–, and is predicted to be a promising asymmetric candidate. Experimentally, FePt intermetallic nanoparticles were synthesized and loaded onto the photocatalytic substrate TiO₂ (denoted as FePt/TiO₂), and CoPt and NiPt were also synthesized as reference samples. X-ray photoelectron spectroscopy and X-ray absorption spectroscopy results reveal the electron enrichment on Pt and depletion on Fe, and DFT calculations uncover that the asymmetric electron distribution on the FePt intermetallic strengthened the CO₂ intermediate’s adsorption and C–C coupling, reducing the free energy barrier to 0.68 eV. As a result, FePt/TiO₂ showed efficient production of C₂H₄ (4.8 μmol g^–1 h^–1) in the absence of photosensitizers and scavengers, higher than the amounts obtained with CoPt/TiO₂, NiPt/TiO₂, and TiO₂ (2.1, 1.5, and 0 μmol g^–1 h^–1, respectively). This study offers insights into the design criteria of asymmetric sites to motivate CO₂ photoreduction.

中文翻译：

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通过 Bader 电荷变化对不对称双位点进行计算筛选有助于 CO2 光还原为 C2H4 的 C-C 耦合


构建不对称的双活性位点是在光催化 CO₂ 反应中促进 C₂ 产物形成的有效策略，这归因于抑制的偶极-偶极排斥促进 C-C 耦合。然而，关于不对称程度的信息仍然缺失，这使得不对称位点的精确设计成为一个挑战。在此，选择金属间化合物中的 Bader 电荷变化 （Δq） 作为选择不对称位点的描述符，其中发现 Δq 与 C₂ 中间体的吸附能之间存在线性关系。从 66 种金属间化合物候选物中，FePt 脱颖而出，Δq = 0.503 e^–，预计是一种很有前途的不对称候选物。实验合成了 FePt 金属间化合物纳米颗粒并将其负载到光催化底物 TiO₂ （表示为 FePt/TiO₂） 上，还合成了 CoPt 和 NiPt 作为参考样品。X 射线光电子能谱和 X 射线吸收光谱结果揭示了 Pt 上的电子富集和 Fe 上的消耗，DFT 计算揭示了 FePt 金属间化合物上的不对称电子分布加强了 CO₂ 中间体的吸附和 C-C 耦合，将自由能势垒降低到 0.68 eV。结果，在没有光敏剂和清除剂的情况下，FePt/TiO₂ 显示出 C₂H₄ （4.8 μmol g^–1 h^–1） 的高效产生，高于使用 CoPt/TiO₂、NiPt/TiO₂ 和 TiO₂ 获得的量（分别为 2.1、1.5 和 0 μmol g^–1 h^–1）。 本研究为不对称位点的设计标准提供了见解，以激励 CO₂ 光还原。