用NH4F络合还原法制备的炭载Pd催化剂对甲酸分解的催化性能和甲酸氧化的电催化性能

摘要

直接甲酸燃料电池(DFAFC)的两大问题是炭载Pd(Pd/C)催化剂对甲酸氧化的电催化稳定性不好和Pd催化剂能催化甲酸分解.发现用NH4F络合还原法制备的NH4F修饰Pd/C催化剂对甲酸氧化的电催化活性要比Pd/C催化剂好大约20％,电催化稳定性也要稍优于Pd/C催化剂.在120 s内和30℃下,甲酸在Pd/C催化剂上分解产生38 mL气体,但在NH4F修饰Pd/C催化剂上基本上不分解,因此NH4F修饰主要能抑制Pd催化剂催化分解甲酸的能力,而且又能在一定程度上提高Pd/C催化剂对甲酸氧化的电催化性能.%The poor electrocatalytic stability of the Pd/C catalyst and the catalytic decomposition of formic acid by the Pd/C catalyst are two problems for direct formic acid fuel cell (DFAFC). The results show that the electrocatalytic activity of the NH4F modified Pd/C catalyst prepared with NH4F complexing reduction method for formic acid oxidation is about 20% better than that of the Pd/C catalyst. The electrocatalytic stability of the title catalyst is also better than that of the Pd/C catalyst. Furthermore, formic acid can be decomposed on the Pd/C catalyst to produce 38 mL gas in 120 s at 30 ℃. However, formic acid is almost not decomposed on the NH4F modified Pd/C catalyst. The NH4F modification can mainly inhibit the catalytic ability for the decomposition of formic acid on the Pd/C catalyst. In addition, it can increase in a certain extent the electrocatalytic performance of the Pd/C catalyst for the formic acid oxidation.