Preparation Of Cellulose/MOF Composites And Their Applications In The Self-Powered Removal Of Atmospheric Pollutants

Atmosphere contamination triggered by solid particulate matter（PM）or volatile organic compounds（VOCs）has become an issue of great concern today.Traditional physical filtration mechanisms are inefficient in filtering submicron particulate matter.For the removal of VOCs,there are also various methods such as electrocatalysis and metal catalytic oxidation.However,electrocatalytic oxidation requires an external power source,while metal-catalyzed oxidation relies on very expensive and rather limited novel metals,which increases energy consumption and costs.Therefore,it is necessary to develop a simple,efficient and low-cost air purification technology.In this work,cellulose aerogel/Ni-HITP composite and cellulose carbon aerogel/NH₂-MIL-125（Ti）composite were synthesized using cellulose as the carrier of metal-organic frameworks（MOFs）.The two composites were combined with triboelectric nanogenerators（TENGs）to build self-powered air filter and TENG-enhanced gaseous acetaldehyde absorption and photocatalytic degradation system.The application of TENG technology on the basis of traditional fibrous air filtration materials and photocatalytic materials can achieve efficient submicron particle removal and improved gaseous acetaldehyde photocatalytic efficiency.Simultaneously,the mechanism of TENG enhanced submicron particle filtration and gaseous acetaldehyde photocatalytic degradation was revealed.This paper mainly includes the following two aspects of work:（1）A self-powered air filter based on respiratory-driven triboelectric nanogenerator（R-TENG）structure is proposed,which allows real-time monitoring of respiratory indicators while efficiently filtering submicron particles.The self-powered air filter consists of conductive cellulose aerogel/Ni-HITP composite and poly（vinylidene fluoride）（PVDF）membrane,both of which serve as filter materials and simultaneously as a friction layer to form the R-TENG.Based on the combination of traditional physical filtration mechanism and electrostatic adsorption,the air filter can achieve up to 98.4%,97.3%and 95.0%filtration efficiency for PM_1.0,PM_0.5 and PM_0.3,respectively.（2）Combining TENG and photocatalytic technology,a self-powered acetaldehyde removal method based on cellulose carbon aerogel/metal-organic framework（CCA/NH₂-MIL-125（Ti））composite is demonstrated.NH₂-MIL-125（Ti）was loaded onto a conductive cellulose carbon aerogel（CCA）and connected with a piston-based triboelectric nanogenerator（P-TENG）to construct a P-TENG-enhanced gaseous acetaldehyde absorption and photocatalytic removal system.The P-TENG can induce an electric field on the CCA/NH₂-MIL-125（Ti）composite,and enhance photocatalytic degradation of acetaldehyde.The removal rate of acetaldehyde driven by P-TENG was 48%,which is 1.29 times better than the system without P-TENG.The removal efficiency of acetaldehyde can reach 65%after 30 min driven by a simulated breeze（3.0 m/s）.This study proposed that higher electron-hole separation efficiency was achieved by an external electric field applied by TENG,while the mechanism of P-TENG-enhanced photocatalytic degradation of acetaldehyde was analyzed by electron spin resonance（ESR）technique.