TiO_(2)纳米粉在水中通过摩擦还原CO_(2)

Reduction of CO_(2) by TiO_(2) nanoparticles through friction in water

纳米材料与特氟龙磁力搅拌棒之间的摩擦被发现可导致磁力搅拌条件下的染料降解.本文对磁力搅拌条件下TiO_(2)纳米粉还原CO_(2)进行了研究.在充有CO_(2)的100mL石英反应器中,在50mL的水中分散1.00gTiO_(2)纳米粉,经过50 h磁力搅拌可产生6.65×10^(–6)(体积分数,下同)CO,2.39×10^(–6)CH_4和0.69×10^(–6)H_(2);而如果没有TiO_(2)纳米粉,则只能产生2.22×10^(–6)CO和0.98×10^(–6)CH_(4).对含有分散TiO_(2)纳米粉的水同时采用4个磁力搅拌棒,50 h磁力搅拌产生的气体进一步提高到19.94×10^(–6)CO,2.33×10^(–6)CH_(4)和2.06×10^(–6)H_(2).基于TiO_(2)纳米粉通过摩擦吸收机械能并被激发产生电子-空穴对,建立了TiO_(2)纳米粉对CO_(2)和水还原的催化机理.本发现表明,纳米材料能够通过摩擦利用机械能进行CO_(2)的还原,从而为开发利用环境中的机械能提供了一个新的方向.

The friction between some nanomaterials and teflon magnetic stirring rods has recently been found responsible for dye degradation by magnetic stirring in dark.In this work,a study is conducted on the reduction of CO_(2) by TiO_(2) nanoparticles under magnetic stirring in water.In a 100-mL reactor filled with 50-mL water,1.00-g TiO_(2) nanoparticles and 1-atm CO_(2),50-h magnetic stirring results in the formation of 6.65×10^(–6)(volume fraction)CO,2.39×10^(–6) CH4 and 0.69×10^(–6) H2;while in a reactor without TiO_(2) nanoparticles,the same magnetic stirring leads only 2.22×10^(–6) CO and 0.98×10^(–6) CH4 to form.Four magnetic stirring rods are used simultaneously to further enhance the stirring,and 50-h magnetic stirring can form 19.94×10^(–6) CO,2.33×10^(–6) CH4,and 2.06×10^(–6) H2.A mechanism for the catalytic role of TiO_(2) nanoparticles in the reduction of CO_(2) and H2O is established,which is based on the excitation of electron-hole pairs in TiO_(2) by mechanical energy absorbed through friction.This finding clearly demonstrates that nanostructured semiconductors are able to utilize mechanical energy obtained through friction to reduce CO_(2),thus providing a new direction for developing and utilizing the mechanical energy harvested from ambient environment.