The hydrogenation of CO₂ to methanol over Cu-nanoparticles supported on TiO₂ nanocrystals was studied at 30 bar pressure and 200−300 °C. 5 wt% Cu-TiO₂ catalyst was synthesized by a modified hydrothermal method (Cu-TiO₂^HT) and by incipient wetness impregnation method (Cu-TiO₂^IMP). TEM analysis of the Cu-TiO₂^HT catalyst revealed the formation of Cu-nanoparticles (3-5 nm), while larger Cu particle sizes were observed on the Cu-TiO₂^IMP catalyst. The Cu-TiO₂^HT catalyst showed superior catalytic activity (CO₂ conversion ∼ 9.4 %) and methanol selectivity (∼ 96 %) at 200 °C and 30 bar pressure. Low CO₂ conversions (∼6%) and high CO selectivity (∼40 %) was obtained on the Cu-TiO₂^IMP catalyst. Density functional theory (DFT) calculations indicated the CO₂ activation to methanol to proceed via a reverse water gas shift pathway with a significantly lower (93 kJ/mol) CO₂ activation barrier on the Cu-nanoparticles, relative to the larger Cu particles (127 kJ/mol). In addition, the higher selectivity towards methanol over the Cu-TiO₂^HT catalyst was attributed to the higher CO and HCO stability on the Cu nanoparticles. Time of stream (TOS) study of the Cu-TiO₂ catalysts showed no significant deactivation even after 150 h with molar feed ratio 1:3:1 (CO₂:H₂: N₂) at 200 °C.

研究了在30 bar的压力和200-300°C的条件下，负载在TiO ₂纳米晶体上的Cu-纳米颗粒上CO ₂加氢成甲醇的过程。通过改进的水热法（Cu-TiO ₂ ^HT）和初湿浸渍法（Cu-TiO ₂ ^IMP）合成了5 wt％的Cu-TiO ₂催化剂。Cu-TiO ₂ ^HT催化剂的TEM分析表明形成了铜纳米粒子（3-5纳米），而在Cu-TiO ₂ ^IMP催化剂上观察到了较大的Cu粒径。Cu-TiO ₂ ^HT催化剂显示出优异的催化活性（CO ₂在200°C和30 bar的压力下，甲醇转化率约为9.4％），甲醇选择性约为96％。在Cu-TiO ₂ ^IMP催化剂上获得了低的CO ₂转化率（〜6％）和高的CO选择性（〜40％）。密度泛函理论（DFT）计算指示的CO ₂活化甲醇经由与显著较低（93千焦/摩尔）CO反向水煤气变换途径进行₂活化在Cu纳米颗粒屏障，相对于较大的Cu粒子（ 127 kJ / mol）。另外，与Cu-TiO ₂ ^HT催化剂相比，对甲醇的更高的选择性归因于对Cu纳米颗粒的更高的CO和HCO稳定性。Cu-TiO ₂的流时间（TOS）研究即使在200℃下进料摩尔比为1：3：1（CO ₂：H ₂：N ₂）的150小时后，催化剂也没有显示出明显的失活。