Herein, we fabricated a series of bimetallic Pt-Ni catalysts supported on mesoporous silica nanorods (mSNR, specific BET surface area of 1802 m² g⁻¹) to study the effect of Ni/Pt ratio on the product selectivity in CO₂ hydrogenation. Both monometallic Pt/mSNR and Ni₅₀Pt₅₀/mSNR catalysts revealed negligible methane selectivity. However, methane became the major product only when increasing the Ni/Pt ratio up to 9. X-ray photoelectron spectroscopy (XPS) and inductively coupled plasma (ICP) characterizations showed that the Pt/Ni ratio on the catalyst surface was appreciably higher than the bulk composition, suggesting the enrichment of Pt on the surface (e.g., Pt/Ni of 61/39 for Ni₅₀Pt₅₀/mSNR catalyst). The Pt/Ni ratio was crucial in determining the CH₄/CO selectivity, and the addition of a tiny amount of Pt could improve the catalytic performance and stability of Ni/mSNR. Among the different catalysts, Ni₉₈Pt₂/mSNR showed the best CO₂ conversion (59%) and CH₄ selectivity (96%) at 400 °C, 0.1 MPa, 9600 mL h⁻¹g_cat⁻¹, and H₂/CO₂ of 3. In-situ DRIFTS and temperature-programmed surface experiments suggested that the dissociated adsorption of CO₂ on the Pt site led to CO*, but the strongly adsorbed CO* cannot be further hydrogenated to CH₄ over the Pt site. In contrast, CO* could be further hydrogenated into CH₄ via CH_xO* intermediates on adjacent Ni sites.

在此，我们制备了一系列负载在介孔二氧化硅纳米棒上的双金属 Pt-Ni 催化剂（m SNR，BET 比表面积为 1802 m ² g ^-1），以研究 Ni/Pt 比对 CO ₂加氢产物选择性的影响. 单金属 Pt/ m SNR 和 Ni ₅₀ Pt ₅₀ / mSNR 催化剂显示出可忽略的甲烷选择性。然而，只有当 Ni/Pt 比率增加到 9 时，甲烷才成为主要产物。 X 射线光电子能谱 (XPS) 和电感耦合等离子体 (ICP) 表征表明，催化剂表面的 Pt/Ni 比率明显高于整体组成，表明 Pt 在表面富集（例如，对于 Ni ₅₀ Pt ₅₀ / m SNR 催化剂，Pt/Ni 为 61/39 ）。Pt/Ni比是决定CH ₄ /CO选择性的关键，加入微量Pt可以提高Ni/ m SNR的催化性能和稳定性。在不同的催化剂中，Ni ₉₈ Pt ₂/ m SNR在 400 °C、0.1 MPa、9600 mL h ^-1 g _cat ^-1和 H ₂ /CO ₂为 3 时显示出最佳的 CO ₂转化率（59%）和 CH ₄选择性（96%）。原位漂移和程序升温表面实验表明，CO ₂在 Pt 位点上的解离吸附导致 CO*，但强烈吸附的 CO* 不能在 Pt 位点上进一步氢化为 CH ₄。相比之下，CO* 可以通过相邻 Ni 位点上的CH _x O* 中间体进一步氢化成 CH ₄。