Among the products of the electrocatalytic reduction of carbon dioxide (CO2RR), CO is currently the most valuable product for industrial applications. However, poor stability is a significant obstacle to CO2RR. Therefore, we synthesized a series of bimetallic organic framework materials containing different ratios of tungsten to copper using a hydrothermal method and used them as precursors. The precursors were then subjected to pyrolysis at 800 °C under argon gas, and the M-N bimetallic sites were formed after 2 h. Loose porous structures favorable for electrocatalytic reactions were finally obtained. The material could operate at lower reduction potentials than existing catalysts and obtained higher Faraday efficiencies than comparable catalysts. Of these, the current density of WCu-C/N (W:Cu = 3:1) could be stabilized at 7.9 mA ‧ cm-2 and the FE of CO reached 94 % at a hydrogen electrode potential of -0.6 V (V vs. RHE). The novel materials made with a two-step process helped to improve the stability and selectivity of the electrocatalytic reduction of CO2 to CO, which will help to promote the commercial application of this technology.

Single-atom Pd clusters anchored on t-BaTiO3 material was synthesized using hydrothermal and ultrasonic methods for the effective piezoelectric catalytic degradation of pollutants using vibration energy. XRD patterns of BaTiO3 loaded with monoatomic Pd were obtained before and after calcining, and showed typical cubic-phase BTO. TEM and HAADF-STEM images indicated single-atom Pd clusters were successfully introduced into the BaTiO3. The piezoelectric current density of the prepared Pd-BaTiO3 binary composite was significantly higher than that of the pristine BaTiO3. Under mechanical vibration, the nanomaterial exhibited a tetracycline decomposition rate of ~95 % within 7 h, which is much higher than the degradation rate of 56.7 % observed with pure BaTiO3. Many of the piezo-induced electrons escaped to the Pd-doped BaTiO3 interface because of Pd’s excellent conductivity. Single-atom Pd clusters help promote the separation of the piezo-induced electrons, thereby achieving synergistic catalysis. This work demonstrates the feasibility of combining ultrasonic technology with the piezoelectric effect and provides a promising strategy for the development of ultrasonic and piezoelectric materials.