High C1 selectivity in alkaline ethanol oxidation reaction over stable Lewis pairs of Pd-MxC@CNT (M = W, Mo and Cr)

A method through SMSI and heterostructure of Pd-MxC@CNT (M = W, Mo and Cr) to construct a stable Lewis acid-base pair was first proposed, showing good EOR activity, stability and C1 selectivity. The Pd-W2C@CNT nanomaterials exhibited the highest mass activity (13.9 A mgPd−1) and C1 selectivity (74.15%). This work not only developed a stable Lewis acid-base pair for electrocatalysis, but the introduction of stable Lewis acid-base pair opened up new ideas for the design of other catalytic reaction catalysts. [Display omitted] •Synthesis of Pd-MxC@CNT material with stable Lewis acid-base pair.•Improving materials stability through stable Lewis acid-base pair and SMSI.•In alkaline EOR the C1 selectivity and mass activity reaches 74.15% and 13.9 A mgPd−1, respectively.•After 20 000 s i-t test, there is still a mass activity of about 7.1 A mgPd−1.•After 20 000 cycles of CV, it still retains 89.7% of the initial activity. Pd-based catalysts have been widely studied as electrocatalysts for ethanol oxidation reaction (EOR) because of their higher oxygenophilic properties. However, there are still some disadvantages such as low activity, poor stability and poor selectivity, which hinder the development of EOR. Herein, a method through strong metal-support interaction (SMSI) and heterostructure of Pd-MxC@CNT (M = W, Mo and Cr) to construct a stable Lewis acid-base pair is proposed. Pd-W2C@CNT nanomaterial showed the highest mass activity (13.9 A mgPd−1), C1 selectivity (74.15%) and stability, better than Pd Black (3.5 A mgPd−1, 7.2%) and Pd@CNT (4.1 A mgPd−1, 7.6%). Ex situ and in situ electrochemical experiments reveal that the introduction of W2C became a stable electron donor for Pd, increasing the electron density of Pd atoms and forming a stable Lewis acidity Pd atoms to weaken the adsorption of intermediates. Reducing the electron density of W2C and forming a stable Lewis basicity W2C to provide sufficient OH adspecies for the reaction, thereby increasing the selectivity of the C1 pathway. Furthermore, the Pd-MxC@CNT synthesized by this method also exhibited excellent EOR activity, stability and C1 selectivity and glycerol oxidation reaction (GOR) performance.