Effective hydrogen production based on formic acid decomposition catalysed by polyvinylpyrrolidone dispersed colloidal platinum nanoparticles using an isobaric process system

Abstract

With its high-volume capacity (53 g H₂ L⁻¹) and low toxicity and flammability under ambient conditions, formic acid is a promising hydrogen energy carrier. It is desirable to invent a catalyst capable of efficiently and selectively decomposing formic acid into H₂. Among the various catalysts, colloidal platinum nanoparticles dispersed in polyvinylpyrrolidone (Pt–PVP) catalyse the formic acid decomposition into H₂ and CO₂ under ambient conditions. In an isochoric process, the amount of H₂ produced in formic acid decomposition catalysed by Pt–PVP, especially at a reaction temperature of 60 °C, tends to approach a constant value with the incubation time. It is predicted that the internal pressure increases due to H₂ production and reaches the equilibrium pressure. In this study, we attempted to improve the amount of H₂ produced during formic acid decomposition with Pt–PVP by maintaining the internal pressure at 1 atm (= 101.3 kPa) with an isobaric process. As a result, the amount of H₂ produced based on formic acid decomposition catalysed with Pt–PVP using an isobaric process system was more than twice that of using an isochoric process system. 650 μmol of Pt–PVP was added to 90 mmol of formic acid aqueous solution (pH 3.5) and reacted at 60.0 °C for 100 min. 42.6 mmol of H₂ was produced and the turnover frequency of Pt–PVP reached 43.8 h⁻¹.