Promotional effects of CuxO on the activity of Cu/ZnO catalyst toward efficient CO oxidation

Abstract

Tailoring the configuration at metal and support interface contributes to an effective pathway for fabricating catalysts of high catalytic performance for scientific and industrial applications. In this study, the CO oxidation activity over spray-pyrolyzed copper doped Zinc oxide (Cu/ZnO) catalyst was enhanced by deposition–precipitation of 1 wt% Copper (CuxO-Cu/ZnO). Copper ions substituted into ZnO caused defects which altered the physiochemical properties of the catalyst and acted as a bridge to accelerate the transfer of charge carriers to the surface, but the promoting effect of CuxO incorporated by deposition–precipitation elevated the catalytic performance of the catalyst. The activation energy of CuxO-Cu/ZnO (24.52 KJ mol−1) was extremely lower than that of 20 wt% Cu/ZnO (32.19 KJ mol−1) catalyst in CO oxidation due to the active and populous Cu(I) species in CuxO-Cu/ZnO. Defects created by the incorporation of Cu species in CuxO-Cu/ZnO catalyst contributed to low-temperature reducibility, oxygen mobility and abundant oxygen vacancies, which played fundamental role in enhancing the activity of CuxO-Cu/ZnO, compared its counterpart. The critical role of the active Cu+ sites was further confirmed by In-situ DRIFTS.