Self‐Powered Electrocatalytic Aldehyde Reforming Fuel Cell for Sustainable H₂ Generation with ∼200% Faradaic Efficiency.

Formaldehyde (HCHO), a promising yet challenging hydrogen carrier, offers a unique opportunity for efficient hydrogen generation through electro‐oxidation, simultaneously eliminating harmful HCHO and contributing to environmental sustainability. This study rises to the challenge by pioneering a hybrid acid/alkali formaldehyde hydrogen production fuel cell (h‐AAFHFC), an integrated system that integrates anodic partial electro‐reforming of aldehydes at low potential with the cathodic hydrogen evolution reaction (HER). The device introduces a new self‐powered paradigm for hydrogen generation, driven by electrochemical neutralization energy (ENE), featuring high Faradaic efficiency for hydrogen production, co‐generation of electricity, and HCOOH. The h‐AAFHFC attains an open‐circuit voltage (OCV) of 1.11 V and a peak power density of 94 mW cm−2, enabling simultaneous hydrogen production at both electrodes with an extraordinary Faradaic efficiency of approximately 200%. This breakthrough marks a transformative shift, moving from traditional electricity‐driven systems to self‐sustaining H2 generation. Our work demonstrates a promising pathway for sustainable hydrogen production, advancing the potential of clean hydrogen energy technologies. [ABSTRACT FROM AUTHOR]