Low-Temperature Hydrogen Production From Liquefied Petroleum Gas via Mechanochemistry

Steam reforming of hydrocarbons is currently the dominant method for hydrogen (H₂) production. As a petroleum refining byproduct rich in butane and propane, liquefied petroleum gas (LPG) offers a more accessible and easily transportable alternative feedstock of hydrocarbons relative to methane-enriched natural gas. However, conventional steam reforming of LPG requires high temperatures to cleave stable C─H bonds, and the inevitable release of carbon oxides as byproducts limits H₂ selectivity (< 76 vol%). To overcome these limitations, we report a low-temperature (37°C) mechanochemical strategy for converting LPG into high-purity H₂ with chromium (Cr) powder. The reaction proceeds without carbon emissions and achieves a high H₂ selectivity of 97.2 vol%, far surpasses that of the thermochemical route (21.3 vol% at 800°C). The H₂ yield rate exhibits at least 50 times enhancement compared to thermochemistry. The H₂ yield ratio reaches 94.6%, nearly 13 times greater than thermochemistry (7.3%). Mechanistically, strong metal-carbon interactions promote dehydrogenation and C─C bond cleavage, and metal-hydrogen interactions determine H₂ selectivity. These findings highlight mechanochemistry as a promising low-temperature, carbon-free approach for sustainable H₂ generation.