Nitrogen-doped graphene nanosheets supported assembled Pd nanoflowers for efficient ethanol electrooxidation

B, N Co-Doping Sequence: An Efficient Electronic Modulation of the Pd/MXene Interface with Enhanced Electrocatalytic Properties for Ethanol Electrooxidation

Improving the electrocatalytic properties by regulating the surface electronic structure of supported metals has always been a hot issue in electrocatalysis. Herein, two novel catalysts Pd/B-N-Ti₃C₂ and Pd/N-B-Ti₃C₂ are used as the models to explore the effect of the B and N co-doping sequence on the surface electronic structure of metals, together with the electrocatalytic properties of ethanol oxidation reaction. The two catalysts exhibit obviously stratified morphology, and the Pd nanoparticles having the same amount are both uniformly distributed on the surface. However, the electron binding energy of Ti and Pd elements of Pd/B-N-Ti₃C₂ is smaller than that of Pd/N-B-Ti₃C₂. By exploring the electrocatalytic properties for EOR, it can be seen that all the electrochemical surface area, maximum peak current density, and antitoxicity of the Pd/B-N-Ti₃C₂ catalyst are much better than its counterpart. Such different properties of the catalysts can be attributed to the various doping species of B and N introduced by the doping sequence, which significantly affect the surface electronic structure and size distribution of supported metal Pd. Density functional theory calculations demonstrate that different B-doped species can offer sites for the H atom from CH₃CH₂OH of dehydrogenation in Pd/B-N-Ti₃C₂, thereby facilitating the progress of the EOR to a favorable pathway. This work provides a new insight into synthesizing the high-performance anode materials for ethanol fuel cells by regulating the supported metal catalyst with multielement doping.

One-pot synthesis of rugged PdRu nanosheets as the efficient catalysts for polyalcohol electrooxidation

Recently, intensive attention has been attracted to the two-dimensional metal nanosheets, owing to their excellent electrocatalytic performance for direct alcohol fuel cells (DAFCs). Herein, PdRu nanosheets have been synthesized successfully by a facile one-pot method. The rugged nanosheet structure provided plentiful surface active sites to enhance the electrocatalytic activity. Moreover, benefiting from the synergistic effect and improved electronic structure, PdRu NSs exhibited splendid electrocatalytic performance in ethylene glycol oxidation reaction (EGOR) and glycerol oxidation reaction (GOR). Specifically, the mass activity of PdRu NSs was 1.72 and 3.69 times over those of Pd NSs and Pd/C catalysts in EGOR. Moreover, PdRu NSs displayed the largest mass activity in GOR, 1.48 and 2.47 times as large as Pd NSs and Pd/C catalysts. The results of stability tests demonstrated that the durability of PdRu NSs was the highest among the obtained catalysts. This work plays a directive role on the in-depth engineering on Pd-based catalysts with nanosheet architectures.