Crystal defect engineering of Bi2Te3 nanosheets by Ce doping for efficient electrocatalytic nitrogen reduction
Jianli Nan, Yongqin Liu, Daiyong Chao, Youxing Fang, Shaojun Dong
Abstract
Electrochemical nitrogen reduction reaction (NRR) is a promising method for the synthesis of ammonia (NH3). However, the electrochemical NRR process remains a great challenge in achieving a high NH3 yield rate and a high Faradaic efficiency (FE) due to the extremely strong N≡N bonds and the competing hydrogen evolution reaction (HER). Recently, bismuth telluride (Bi2Te3) with two-dimensional layered structure has been reported as a promising catalyst for N2 fixation. Herein, to further enhance its NRR activity, a general doping strategy is developed to introduce and modulate the crystal defects of Bi2Te3 nanosheets by adjusting the amount of Ce dopant (denoted as Cex−Bi2Te3, where x represents the designed molar ratio of Ce/Bi). Meanwhile, the crystal defects can be designed and controlled by means of ion substitution and charge compensation. At −0.60 V versus the reversible hydrogen electrode (RHE), Ce0.3−Bi2Te3 exhibits a high NH3 yield (78.2 µg·h−1·mg cat −1 ), a high FE (19.3%), and excellent structural and electrochemical stability. Its outstanding catalytic activity is attributed to the tunable crystal defects by Ce doping. This work not only contributes to enhancing the NRR activity of Bi2Te3 nanosheets, but also provides a reliable approach to prepare high-performance electrocatalysts by controlling the type and concentration of crystal defects for artificial N2 fixation.