MOF-Transformed In_(2)O_(3-x)@C Nanocorn Electrocatalyst for Efficient CO_(2)Reduction to HCOOH

For electrochemical CO_(2) reduction to HCOOH,an ongoing challenge is to design energy efficient electrocatalysts that can deliver a high HCOOH current density(JHCOOH)at a low overpotential.Indium oxide is good HCOOH production catalyst but with low con-ductivity.In this work,we report a unique corn design of In_(2)O_(3-x)@C nanocatalyst,wherein In_(2)O_(3-x)nanocube as the fine grains dispersed uniformly on the carbon nanorod cob,resulting in the enhanced conductivity.Excellent performance is achieved with 84%Faradaic efficiency(FE)and 11 mA cm^(−2)JHCOOH at a low potential of−0.4 V versus RHE.At the current density of 100 mA cm^(−2),the applied potential remained stable for more than 120 h with the FE above 90%.Density functional theory calculations reveal that the abundant oxygen vacancy in In_(2)O_(3-x) has exposed more In^(3+) sites with activated electroactivity,which facilitates the formation of HCOO*intermediate.Operando X-ray absorp-tion spectroscopy also confirms In^(3+) as the active site and the key intermediate of HCOO*during the process of CO_(2) reduction to HCOOH.

All-nanofiber self-powered PTFE/PA66 device for real-time breathing monitor by scalable solution blow spinning technology

All-nanofiber self-powered device was fabricated using simple,low-cost,safe,and scalable solution blow spinning(SBS)technology for real-time respiratory monitor and timely identification of respiratory obstruction clinically.Polytetrafluoroethylene(PTFE)and polyamide-66(PA66)nanofibers were selected as triboelectric pairs,owing to strong ability to gain electrons of PTFE and supply electrons of PA66.Poly(ethylene oxide)(PEO)was added to regulate spinning solution viscosity and prepare PTFE/PEO nanofibers,and the morphology and diameter distribution of nanofibers were discussed.PTFE nanofiber film was obtained after the decomposition of PEO in PTFE/PEO nanofiber and melt flow of PTFE pellets in a limited region,and possessed a tensile strength of 1.05 MPa and elongation at a break of 288.58%.Later,PTFE/PA66 all-nanofiber self-powered device was constructed containing PA66 nanofibers,and Au deposition film was used as electrodes by magnetron sputtering.The as-obtained device showed robust electrical performance with an open circuit voltage of~110 V at a loading force of 10 N,a short-circuit current of~5 uA at a loading force of 10 N and a frequency of 4 Hz,a maximum power density of 562 mW·m^(–2),and a current of 3.1 uA at a loading resistance of 30 MΩ.Based on the triboelectric mechanism,the device possessed stable response and effective sensibility for stimuli,was used to monitor human breathing conditions,prevent suffocation,and distinguish slow,normal,and fast breathing,with an output voltage of~0.08 V perceived in one normal respiratory circle.