Inorganic membranes for in-situ separation of hydrogen and enhancement of hydrogen production from thermochemical reactions

Abstract

In the face of a series of global challenges caused by the dependence on fossil fuels, such as the greenhouse effect, energy shortage and air pollution, the development and utilization of hydrogen energy is considered a promising solution. Currently, hydrogen production methods mainly include thermochemical reactions, water electrolysis, biological or plasma processes. Among those alternatives, thermochemical hydrogen production has attracted much attention in recent years, particularly by water-gas shift and steam methane reforming reactions. Improving the hydrogen production efficiency of these reactions is a subject of widespread concern, including the use of inorganic membrane reactors, which have high thermal stability, high mechanical strength and chemical stability. Membranes are used to separate hydrogen generated during thermochemical reactions in-situ. They can not only significantly improve hydrogen production efficiency via Le Chatelier's principle but also significantly increase hydrogen purity. This article summarizes the studies that employed inorganic membranes based on palladium, silica, and zeolite molecular sieve, to separate hydrogen in-situ, and discusses their respective advantages and disadvantages to enhance hydrogen production from thermochemical reactions.