Thermodynamics, kinetics and reaction mechanism of hydrogen production from a novel Al alloy/NaCl/g-C3N4 composite by low temperature hydrolysis

Abstract

Real-time hydrogen production at low temperature can effectively solve the problem of hydrogen storage and transportation in cold area and plateau region. In this study, a novel Al alloy/NaCl/g-C3N4 composite with enhanced low temperature reactivity for hydrogen production has been synthesized by mechanical ball milling method. The feasibility of Al-water reaction at the temperature of 253.15–373.15 K was firstly proved by thermodynamic calculation. The hydrogen generation performance was studied in tap water at 298.15 K and 23 wt% NaCl aqueous solution at low temperature of 253.15–273.15 K. The results indicated that the addition of g-C3N4 can effectively promoted the hydrolysis of activated Al composites. Hydrogen yield of Al alloy/NaCl/g-C3N4 composite with 1 g of g-C3N4 addition reached 1006 mL·gAl−1 and the induction time of reaction was 90 s at 253.15 K, while that of Al alloy was only 230 mL·gAl−1 and 1120s respectively. It was supposed that the addition of g-C3N4 effectively reduced the size of NaCl particles and promoted their uniform distribution in Al matrix and more cracks were generated. The kinetics and reaction mechanism using Al alloy/NaCl/g-C3N4 composite were discussed. This study provides a new idea for the synthesis of Al composites with high reactivity at low temperature.