Energy-saving hydrogen production can be achieved by using renewables or decoupling the sluggish oxygen evolution reaction from overall water splitting, which still needs electricity input. We have realized hydrogen production and water desalination with ondemand electricity output via an electrochemical neutralization chemistry strategy that couples acidic hydrogen evolution and alkaline hydrazine oxidation with ionic exchange. The electrochemical neutralization cells allow efficient use of chemical energy and low-grade heat from the surroundings to output 0.81 kWh electricity per m 3 of hydrogen. Cell function can be rapidly switched to electricity output with a high peak power density up to 85.5 mW cm À 2 or spontaneous hydrogen production at a high rate up to 70.1 mol h À 1 m À 2 without breaking cell operation or changing cell configuration. Fast water desalination is simultaneously achieved at a high salt removal rate of 56.1 mol h À 1 m À 2 without an external electricity supply.

Self‐healable and flexible all‐in‐one self‐powering smartsensing devices have recently attracted great attention. Herein, a flexible all‐in‐one solid‐state electronic system of polyvinyl alcohol (PVA) hydrogel‐based supercapacitors for self‐powering ammonia smartsensors has been fabricated. Self‐healing supercapacitors are prepared by integrating polypyrrole (PPy) and boron cross‐linked PVA/KCl hydrogel as a sandwich configuration, exhibiting large specific capacitance of 244.81 mF cm−2 at 0.47 mA cm−2, and good charging/discharging stability of 2000 cycles, while ammonia sensors are realized by a SnO2/PPy‐modified conductive PVA hydrogel film, demonstrating an excellent sensing behavior toward NH3 vapor under 50 ppb–500 ppm. As a result, self‐healing supercapacitors could well store energy and then self‐power sensing unit for remotely real‐time detection via a smartphone, acquiring high flexibility of energy‐sensing system. With attractive biocompatibility and self‐healing performance toward various environment, this all‐in‐one flexible energy‐smartsensor system would pave the way to novel fabrication process in realization of wearable self‐healing smart devices.

Unhealthy alcohol inhalation is among the top 10 causes of preventable death. However, the present alcohol sensors show poor selectivity among alcohol homologues. Herein, Pt-coated truncated octahedron Au (Pt m @Auto) as the electrocatalyst for a highly selective electrochemical sensor toward alcohol homologues has been designed. The alcohol sensor is realized by distinguishing the electro-oxidation behavior of methanol (MeOH), ethanol (EtOH), or isopropanol (2-propanol). Intermediates from alcohols are further oxidized to CO2 by Pt m @Auto, resulting in different oxidation peaks in cyclic voltammograms and successful distinction of alcohols. Pt m @Auto is then modified on wearable glove-based sensors for monitoring actual alcohol samples (MeOH fuel, vodka, and 2-propanol hand sanitizer), with good mechanical performance and repeatability. The exploration of the Pt m @Auto-based wearable alcohol sensor is expected to be suitable for environmental measurement with high selectivity for alcohol homologues or volatile organic compounds.