Xing Yicheng, Yao Zheng, Li Wenyuan, Wu Wenting, Lu Xiaoqing, Tian Jun, Li Zhongtao, Hu Han, Wu Mingbo
State Key Laboratory of Heavy Oil Processing, Institute of New Energy, College of Chemical Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China.
College of Materials Science and Engineering, China University of Petroleum (East China), Qingdao, 266580, P. R. China.
Angew Chem Int Ed Engl. 2021 Apr 12;60(16):8889-8895. doi: 10.1002/anie.202016888. Epub 2021 Mar 10.
H O as a well-known efficient oxidant is widely used in the chemical industry mainly because of its homolytic cleavage into OH (stronger oxidant), but this reaction always competes with O generation resulting in H O waste. Here, we fabricate heterogeneous Fenton-type Fe-based catalysts containing Fe-N sites and Fe/Fe C nanoparticles as a model to study this competition. Fe-N in the low spin state provides the active site for OH generation. Fe/Fe C, in particular Fe C, promotes Fe-N sites for the homolytic cleavages of H O into OH, but Fe/Fe C nanoparticles (Fe as the main component) with more electrons are prone to the undesired O generation. With a catalyst benefiting from finely tuned active sites, 18 % conversion rate for the selective oxidation of methane was achieved with about 96 % selectivity for liquid oxygenates (formic acid selectivity over 90 %). Importantly, O generation was suppressed 68 %. This work provides guidance for the efficient utilization of H O in the chemical industry.
过氧化氢作为一种著名的高效氧化剂，在化学工业中被广泛使用，主要是因为它能均裂生成羟基自由基（更强的氧化剂），但该反应总是与氧气生成相竞争，导致过氧化氢的浪费。在此，我们制备了含有铁氮位点和铁/碳化铁纳米颗粒的非均相类芬顿型铁基催化剂作为模型来研究这种竞争。低自旋态的铁氮为羟基自由基的生成提供了活性位点。铁/碳化铁，特别是碳化铁，促进铁氮位点将过氧化氢均裂生成羟基自由基，但电子较多的铁/碳化铁纳米颗粒（以铁为主要成分）容易发生不期望的氧气生成。通过一种具有精细调控活性位点的催化剂，实现了甲烷选择性氧化18%的转化率，对液态含氧化合物的选择性约为96%（甲酸选择性超过90%）。重要的是，氧气生成被抑制了68%。这项工作为化学工业中过氧化氢的高效利用提供了指导。
