Introducing polyethyleneimine (PEI) into the electrospun fibrous membranes containing diiron mimics of [FeFe]-hydrogenase: Membrane electrodes and their electrocatalysis on proton reduction in aqueous media

A number of fibrous membranes with cellulose acetate as a matrix and functionalised with diiron mimics of the diiron subunit of [FeFe]-hydrogenase were prepared by electrospinning technique . Four mimics, [Fe 2 (μ-edt) (CO) 6 ] ( 1 ), [Fe 2 {μ-SCH 2 CH(CH 2 OH)S}(CO) 6 ] ( 2 ), [Fe 2 {(μ-S) 2 (C 6 O 2 H 4 )}(CO) 6 ] ( 3 ) and [Fe 2 {μ-SCH 2 CH(OH)CH 2 (OH)} 2 (CO) 6 ] ( 4 ), bearing 0, 1, 2 and 4 hydroxyl group(s) were incorporated into the electrospun fibrous membranes ( EFM s). To improve the conductivity of the EFM s, graphene oxide was chemically gratified onto cellulose acetate. The resultant EFM s membranes were characterized using infrared spectroscopic, thermogravimetric and scanning electron microscopic techniques. The electrochemical behaviours and electrocatalytic performance on proton reduction of the membrane electrodes assembled from the EFM s showed in aqueous media that the membrane ( M2 ) containing complex 2 is most durable and exhibited the best catalytic performance. To the electrospinning system containing complex 2 was further doped with basic polymer PEI to enhance tentatively proton transfer during the electrocatalysis of proton reduction. Our results showed that the presence of PEI in the EFM s did improve the electrocatalytic performance of proton reduction, presumably due to the enhancement in proton transfer in the catalysis.