Superporous P(2-hydroxyethyl methacrylate) cryogel-M (M:Co, Ni, Cu) composites as highly effective catalysts in H2 generation from hydrolysis of NaBH4 and NH3BH3

•Superporous p(SPM) cryogel-M (M:Co, Cu, Ni) for H2 generation.•Faster H2 production in salty water than in DI water by p(SPM)-Co cryogel composite.•Higher H2 production rate up to 2836 ± 90 from 1000 ± 53 (ml H2) (g of Co min)−1.•Reusable p(SPM)-Co cryogel catalyst with 100% conversion and catalytic activity.

Highly porous p(2-hydroxyethyl methacrylate) p(HEMA) cryogels were synthesized via cryopolymerization technique and used as template for Co, Ni, and Cu nanoparticle preparation, then as composite catalyst systems in H2 generation from hydrolysis of both NaBH4 and NH3BH3. Due to their highly porous and open microstructures, p(HEMA)-Co cryogel composites showed very effective performances in H2 production from hydrolysis of both chemical hydrides. The characterization of p(HEMA) cryogels, and their metal composites was determined via various techniques including swelling experiments, digital camera images, SEM and TEM images, AAS and TGA measurements. The effect of various parameters on the hydrolysis reaction of NaBH4 such as metal types, concentration of chemical hydrides, amounts of catalyst, alkalinity of reaction medium and temperature were investigated in detail. It was found that Co nanoparticles are highly active catalysts in H2 generation reactions from both hydrides. The hydrogen generation rate (HGR) of p(HEMA)-Co was 1596 (mL H2) (min)−1 (g of Co)−1 which is quite good in comparison to reported values in the literature. Furthermore, kinetic parameters of p(HEMA)-Co metal composites such as energy, enthalpy and entropy were determined as Ea = 37.01 kJmol−1, ΔH# = 34.26 kJmol−1, ΔS# = −176,43 Jmol−1 K−1, respectively.

Graphical abstractSuperporous p(HEMA)-M cryogel composites (M:Co, Ni, Cu).Figure optionsDownload full-size imageDownload as PowerPoint slide