Pr_(2)O_(3)/RuO_(2)和Gd_(2)O_(3)/RuO_(2)对甲醇的选择性电催化氧化性能研究  

Selective Electrooxidation of Methanol on Pr_(2)O_(3)/RuO_(2) and Gd_(2)O_(3)/RuO_(2) Catalysts

作　　者：李蒙南 韩洁 张大峰 刘宝忠 LI Meng-nan;HAN Jie;ZHANG Da-feng;LIU Bao-Zhong(College of Chemistry and Chemical Engineering,Henan Polytechnic University,Jiaozuo 454003,China)

机构地区：[1]河南理工大学化学化工学院,河南焦作454003

出　　处：《稀土》2022年第5期1-10,共10页Chinese Rare Earths

基　　金：国家自然科学基金项目(52071135;51871090,U1804135);河南省自然科学基金项目(182300410196)。

摘　　要：由于电解水阳极析氧反应(Oxygen Evolution Reaction, OER)过电位较高,增加了电解水制氢的整体能耗。故本实验采用热力学上有利的甲醇氧化反应(Methanol Oxidation Reaction, MOR)替代OER,尝试缓解OER对酸性电解水制氢的能耗制约。通过热解法制备了Pr_(2)O_(3)/RuO_(2)和Gd_(2)O_(3)/RuO_(2)催化剂,不仅能催化甲醇生成增值的甲酸(HCOOH),而且可以使MOR过程与析氢反应耦合,生成高纯的H2。电化学分析测试表明,在含CH3OH(2.5 mol·L-1)的H2SO4(0.5 mol·L-1)电解质溶液中,电流密度达到10 mA·cm^(-2)时,Pr_(2)O_(3)/RuO_(2)和Gd_(2)O_(3)/RuO_(2)的极化电位分别为1.208 V和1.191 V,远低于纯RuO_(2)的1.40 V。对产物分析发现,在转移电子数约为200 C时,Pr_(2)O_(3)/RuO_(2)和Gd_(2)O_(3)/RuO_(2)产生甲酸的电流效率分别为51.4%和54.7%。上述结果表明,甲醇选择性氧化制甲酸反应对酸性OER过程展现出了极具潜力的替代价值,能够显著降低电解水制氢的成本。The sluggish kinetics of oxygen evolution reaction(OER) leads to a high energy consumption of H2production via water splitting. In this work, a thermodynamically favorable methanol oxidation reaction(MOR) on RuO_(2)is proposed as an alternative to OER in acidic electrolyte to achieve an energy-saving H2production. Rare earth oxides, Gd_(2)O_(3)and Pr_(2)O_(3), was used to modulate the catalytic property of RuO_(2)for MOR, which can facilitate the dissociation of water molecule to provide the adsorbed OH species for MOR. As expected, at the current density of 10 mA·cm^(-2)the reaction potential of MOR on both Gd_(2)O_(3)/RuO_(2)and Pr_(2)O_(3)/RuO_(2)catalysts has been greatly reduced from 1.40 V on pure RuO_(2)(py-RuO_(2)) to 1.191 V and 1.208 V in H2SO4(0.5 mol·L-1) electrolyte solution containing CH3OH(2.5 mol·L-1), respectively. Moreover, the main product of MOR was confirmed to be formic acid with the selectivity up to 54.7% on Gd_(2)O_(3)/RuO_(2)and 51.4% on Pr_(2)O_(3)/RuO_(2). This value-added product would contribute to a further cost-reduction in H2generation. The results indicate a promising utilization of MOR to replace the sluggish OER in acidic media, which can significantly reduce the cost of hydrogen production from water splitting.

关 键 词：电催化 甲醇氧化 Pr_(2)O_(3) Gd_(2)O_(3) RuO_(2) 

分 类 号：O69[理学—化学]