Enhanced room temperature gas sensing performance of ZnO with atomic-level Pt catalysts facilitated by the polydopamine mediator

The poor sensitivity of metal-oxide(MO)sensing material at room temperature can be enhanced by the modi-fication of noble metal catalysts.However,the large size and uncontrollable morphology of metal nanoparticles(NPs)compromise the catalytic activity and selectivity.Downsizing metal NPs to the atomic level is a promising solution because it offers high activity and selectivity.Nevertheless,a facile and universal approach for stable loading atomic-level metal on MO-based sensing materials is still challenging.Herein,we present a strategy to construct synergetic coordination interface for uniform loading of atomic-level metal catalysts on MO-based gas-sensing materials using a difunctional mediator layer.In this work,atomically dispersed Pt catalysts are coor-dinately anchored on ZnO nanorods(NRs)using polydopamine(PDA)as a mediator.As a result,compared with pristine ZnO NRs,a six-fold enhanced response of 18,489%is achieved toward 100 ppm NO_(2)on 0.20 wt%Pt-ZnO@PDA-1.5 nm,and the selectivity is also promoted.Such sensitivity is higher than that of most reported noble metal-modified MO NO_(2)-sensing materials.This work provides a simple and general strategy for building highly sensitive and selective gas-sensing materials using atomic-level noble metal catalyst.