银掺杂氮化碳负载型Pd基催化剂的优化制备及在甲酸催化脱氢中的应用

Optimization of Pd-based catalyst supported on silver-doped carbon nitride and its catalytic activity in formic acid dehydrogenation

摘要:

通过硝酸银预修饰三聚氰胺高温煅烧获得一种银掺杂氮化碳（Ag-C3N4）载体，进而基于该载体制备了Pd基负载型催化剂，该催化剂在甲酸催化脱氢中展示了良好的催化活性。通过XRD、TEM、Mapping和XPS等对银掺杂氮化碳载体和催化剂的晶相结构与微观结构进行了表征。结果表明：高温煅烧硝酸银预修饰的三聚氰胺前驱体可以实现银物种直接掺杂入氮化碳体相获得一种含银氮化碳载体（Ag-C3N4），银的引入调变了氮化碳载体的晶相结构和微观形貌，进一步研究发现基于该载体制备的Pd基催化剂在甲酸分解制氢反应中展现了良好的催化活性。催化剂活性测试表明优化后的Ag3%-C3N4-Pd催化剂样品在323K时，甲酸分解TOF值可达991h-1，其高于未经Ag掺杂氮化碳负载的Pd基催化剂。通过硝酸银预修饰三聚氰胺有助于调变氮化碳载体的微结构，提高氮化碳负载型催化剂的催化活性。

Abstract:

Silver-doped C3N4 supports (Ag-C3N4) were prepared by high temperature calcination of melamine pre-modified by silver nitrate, and then a Pd-based supporting catalyst was prepared based on this catalyst supports. The catalyst showed good catalytic activity in the catalytic dehydrogenation of formic acid. The crystal phase structure and microstructure of the catalyst were characterized by XRD, TEM, Mapping and XPS. The results show that Ag species can be doped into the bulk of C3N4 to obtain an Ag-containing C3N4 supports by calcining melamine pre-modified by silver nitrate at high temperature. It can be found that the introduction of Ag species can modulate the crystal phase structure and microstructure of C3N4. And the Pd-base catalysts supported onto our supports showed a good catalytic activity in the hydrogen reaction of formic acid decomposition. The catalyst activity test showed that the TOF of the optimized Ag3%-C3N4-Pd catalyst sample could reach 991h-1 at 323K, which is obviously higher than the Pd-based catalyst supported on C3N4 without any modification. The premodification of melamine with silver nitrate is helpful to obtain good catalyst support and to prepare high performance catalyst.