Ren Bowen, Jin Qiuyan, Li Yinwei, Li Yan, Cui Hao, Wang Chengxin
State Key Laboratory of Optoelectronic Materials and Technologies, School of Materials Science and Engineering, The Key Laboratory of Low-Carbon Chemistry & Energy Conservation of Guangdong Province, Sun Yat-sen University, Guangzhou 510275, China.
School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China.
ACS Appl Mater Interfaces. 2020 Mar 11;12(10):11607-11615. doi: 10.1021/acsami.9b21575. Epub 2020 Mar 2.
Though transition-metal-based materials have emerged as the most promising alternatives to Pt-based electrocatalysts in hydrogen evolution reaction (HER), only a few of them (Fe-, Co-, Ni-, W-, and Mo-based materials) are used as efficient HER electrocatalysts, while others are generally considered as HER-inactive materials with poor activities. Here, a theory-guided experiment is carried out to activate titanium dioxide as a new efficient HER electrocatalyst. First-principles simulations indicate that the hydrogen adsorption free energy could be optimized through tuning the structural and electronic properties of TiO. Then Cu-doped amorphous TiO is successfully prepared based on the theoretical results. The activated TiO expectedly shows excellent HER performance with a low overpotential of 92 mV at 10 mA cm in alkaline media, which is far superior to that of the crystalline TiO (over 400 mV). The origin of HER activity is further investigated in detail. The corrugation of the amorphous surface helps stabilize the adsorbed water molecule, crucial for the water dissociation of the Volmer step. The Cu doping can strengthen the orbital hybridization of H1s and O2p favoring the hydrogen adsorption/desorption and improve the electrical conductivity. Our work highlights the great potential of traditionally inactive materials in HER electrocatalysis and helps deepen our understanding of the catalytic mechanism.
尽管基于过渡金属的材料已成为析氢反应（HER）中铂基电催化剂最有前景的替代品，但其中只有少数几种（铁基、钴基、镍基、钨基和钼基材料）被用作高效的HER电催化剂，而其他材料通常被认为是活性较差的HER非活性材料。在此，开展了一项理论指导实验，以激活二氧化钛作为一种新型高效HER电催化剂。第一性原理模拟表明，通过调整TiO的结构和电子性质，可以优化氢吸附自由能。然后基于理论结果成功制备了铜掺杂非晶态TiO。预期该活化后的TiO在碱性介质中表现出优异的HER性能，在10 mA cm时过电位低至92 mV，远优于结晶TiO（超过400 mV）。进一步详细研究了HER活性的起源。非晶态表面的波纹有助于稳定吸附的水分子，这对Volmer步骤中的水离解至关重要。铜掺杂可以增强H1s和O2p轨道杂化，有利于氢的吸附/脱附，并提高电导率。我们的工作突出了传统非活性材料在HER电催化中的巨大潜力，并有助于加深我们对催化机理的理解。
