Highly Catalytic Selectivity for Hydrogen Peroxide Generation from Oxygen Reduction on Nd-Doped Bi₄Ti₃O₁₂Nanosheets

The electrochemical two-electron oxygen reduction reaction (2e –1 ORR) is a promising route for renewable H 2 O 2 generation as an alternative method to the anthraquinone process. The development of efficient and highly selective catalytic materials is a highly meaningful and challenging subject due to the strong competition from the traditional four-electron oxygen reduction reaction (4e –1 ORR). Here, we synthesized bismuth titanate (Bi 4 Ti 3 O 12 ) nanosheets as a type of new electrocatalyst for H 2 O 2 generation from 2e –1 ORR. The structure of the Bi 4 Ti 3 O 12 nanosheets is characterized by high-resolution transmission electron microscopy (HRTEM) and X-ray techniques. The electrochemical measurements show that the obtained bismuth titanate (Bi 4 Ti 3 O 12 ), especially the neodymium (Nd)-substituted Bi 4 Ti 3 O 12, has high catalytic activity and selectivity for O 2 to H 2 O 2 . For the ORR catalyzed by Bi 4 Ti 3 O 12 nanosheets, 83–89% H 2 O 2 selectivity can be achieved in a wide range of potentials, while Nd-substituted Bi 4 Ti 3 O 12 nanosheets afford a higher selectivity of 93–95%. Moreover, in a two-chamber H-cell, H 2 O 2 production of 208 mol kg cat –1 can be achieved at 0.36 V under the catalysis of Nd-substituted Bi 4 Ti 3 O 12 for 1 h with a Faraday efficiency of 97.6%. The high O 2 -to-H 2 O 2 catalytic performance could be ascribed to the large surface area and the abundant exposed active sites of the nanosheets.