关键词: 催化剂, 制氢, 活性, 焙烧, 晶粒度

Abstract:

Methanol is a crucial hydrogen energy transporter, and producing hydrogen through methanol decomposition provides a practical solution to the challenges associated with transporting and storing hydrogen. Industrial methanol decomposition typically employs copper-based catalysts, which are usually synthesized through neutralization precipitation and calcination to yield the desired metal oxides. However, traditional single-step calcination often leads to the aggregation of copper species and an increase in crystallite size, which limits catalytic activity and reduces the accessibility of active sites. This study investigated the phase composition of the zincian malachite precursor for copper-based catalysts. By separating the precursor calcination into dehydroxylation and decarbonation phases, a novel stepwise calcination technique was developed that effectively prevents excessive thermal degradation, which can result in the sintering of active particles. The catalyst derived from stepwise calcination exhibits enhanced structural properties compared to conventional single-step calcined catalysts: the size of the CuO crystallites decreases from 9.0nm to 6.3nm, and the most probable pore diameter decreases from 36.5nm to 8.1nm, along with more ordered pore channel structures. Consequently, the stepwise calcination catalyst has a lower initiation temperature for methanol decomposition than conventional catalysts, leading to significantly improved methanol conversion efficiency and hydrogen selectivity.

Key words: catalyst, hydrogen production, reactivity, calcination, grain size