am9b21575_si_001.pdf (2 MB)
Activating Titanium Dioxide as a New Efficient Electrocatalyst: From Theory to Experiment
journal contribution
posted on 2020-02-28, 21:31 authored by Bowen Ren, Qiuyan Jin, Yinwei Li, Yan Li, Hao Cui, Chengxin WangThough
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 TiO2. Then Cu-doped amorphous TiO2 is successfully
prepared based on the theoretical results. The activated TiO2 expectedly shows excellent HER performance with a low overpotential
of 92 mV at 10 mA cm–2 in alkaline media, which
is far superior to that of the crystalline TiO2 (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.