Characteristics of emulsion preparation in an ultrasonic microreactor: cavitation, droplet size and energy efficiency

The development of self-supporting electrodes using natural wood is promising for energy storage and conversion but still challenging. Here, the nitrogen-doped carbonized wood electrode decorated with copper nanoparticles is synthesized to escalate its capacitive performance and HER. Cu1.0NPs@NCW-1000 exhibits a high specific capacitance of 10.39 F cm -2 at 1 mA cm -2. The symmetric supercapacitor achieves an energy density of 0.59 mWh cm -2 at 3.5 mW cm -2 while achieving a capacitance retention of 89.51 % after 8,000 cycles. Cu1.0NPs@NCW-1000 also displays good HER activity, comprising an overpotential of 100.43 mV at 10 mA cm -2 and a Tafel slope of 95 mV dec -1. Its outstanding properties were attributed to doping -nitrogen, high specific surface area, hierarchical porous structure, and the interaction between Cu NPs and NCW, which increased active sites and accelerated charge transfer. This work provides a new strategy for the preparation of self-supported