Electrochemical NO3 - Reduction Catalyzed by Atomically Precise Ag30Pd4 Bimetallic Nanocluster: Synergistic Catalysis or Tandem Catalysis?

作者：Qin, Lubing; Sun, Fang; Gong, Zhiheng; Ma, Guanyu; Chen, Yan; Tang, Qing^*; Qiao, Liang; Wang, Renheng^*; Liu, Zhao-Qing; Tang, Zhenghua^*

来源：ACS Nano, 2023, 17(13): 12747-12758.

DOI：10.1021/acsnano.3c03692

• electrochemical NO3 (-) reduction
• Ag30Pd4 nanocluster
• insitu FTIR
• DFT calculations
• tandem catalysis

Electrochemically converting NO3 (-) compoundsinto ammonia represents a sustainable route to remove industrial pollutantsin wastewater and produce valuable chemicals. Bimetallic nanomaterialsusually exhibit better catalytic performance than the monometalliccounterparts, yet unveiling the reaction mechanism is extremely challenging.Herein, we report an atomically precise [Ag30Pd4 (C6H9)(26)](BPh4)(2) (Ag30Pd4) nanocluster as a model catalysttoward the electrochemical NO3 (-) reductionreaction (eNO(3) -RR) to elucidate the differentrole of the Ag and Pd site and unveil the comprehensive catalyticmechanism. Ag30Pd4 is the homoleptic alkynyl-protectedsuperatom with 2 free electrons, and it has a Ag30Pd4 metal core where 4 Pd atoms are located at the subcenterof the metal core. Furthermore, Ag30Pd4 exhibitsexcellent performance toward eNO(3) (-)RRand robust stability for prolonged operation, and it can achieve thehighest Faradaic efficiency of NH3 over 90%. Insitu Fourier-transform infrared study revealed that a Agsite plays a more critical role in converting NO3 (-) into NO2 (-), while the Pd site makesa major contribution to catalyze NO2 (-) into NH3. The bimetallic nanocluster adopts a tandemcatalytic mechanism rather than a synergistic catalytic effect ineNO(3) -RR. Such finding was further confirmedby density functional theory calculations, as they disclosed thatAg is the most preferable binding site for NO3 (-), which then binds a water molecule to release NO2 (-). Subsequently, NO2 (-) cantransfer to the vicinal exposed Pd site to promote NH3 formation.

• 单位
  广州大学; 重庆大学