Synthesis, characterization, and catalytic properties of nano-SnO by chemical vapor transport (CVT) process under CO-CO2 atmosphere

Abstract

Chemical vapor transport (CVT) process is a simple and efficient method for synthesizing nano-SnO products, and previous references reveal that the CVT process is characterized as high temperature and long synthesis time. Our previous studies indicated that SnO2 was easily reduced to solid-state SnO and then volatilized as gaseous SnO under certain CO-CO2 atmosphere, so that a novel CVT process under CO-CO2 atmosphere was proposed in the present work. The nano-SnOs synthesized by the CVT under 15vol% CO/(CO+CO2) atmosphere were characterized using XRD, SEM, TEM, XPS, etc. The results showed that tetragonal structure nano-SnO diskette and sphere with uniform granularity of 50–100nm were obtained with high purity. During the CVT process, CO-CO2 mixed gases could reduce SnO2 to SnO and act as a CVT medium to take away the newly formed gaseous SnO, resulting in the decrease of the partial pressure of SnO. In addition, the nano-SnOs could enhance the SCR deNOx activity of activated carbon (AC), and both the reaction temperature window of AC and the NO conversion were increased if the AC was coated by nano-SnOs.