▎ 摘　　要

NOVELTY - A membrane electrode comprises a polymer film as a substrate, and a substrate layer formed of a paper-like graphene material or a paper-like graphene-based nanocomposite material. USE - Membrane electrode for use in electrochemical gas sensor for gas detection, where gas is formaldehyde, chlorine, oxygen, carbon monoxide, hydrogen sulfide, sulfur dioxide, nitrogen oxides or hydrogen (all claimed). ADVANTAGE - The electrode has high gas responsiveness, high responsiveness, high sensitivity, and low detection limit. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for the following: (1) a method for preparing membrane electrode (2) an electrochemical gas sensor.