Search

In this paper, we present a solvothermal synthesis of iron phosphide electrocatalysts using a triphenylphosphine (TPP) precursor. The synthetic protocol generates Fe 2 P phase at 300 °C and FeP phase at 350 °C. To enhance the catalytic activities of obtained iron phosphide particles heat-treatments were carried out at elevated temperatures. Annealing at 500 °C under reductive atmosphere induced structural changes in the samples: (i) Fe 2 P provided a pure Fe 3 P phase (Fe 3 P−500 °C) and (ii) FeP transformed into a mixture of iron phosphide phases (Fe 2 P/FeP−500 °C). Pure Fe 2 P films was prepared under argon atmosphere at 450 °C (Fe 2 P−450 °C). The electrocatalytic activities of heat-treated Fe 2 P−450 °C, Fe 3 P−500 °C, and Fe 2 P/FeP−500 °C catalysts were studied for hydrogen evolution reaction (HER) in 0.5 M H 2 SO 4. The HER activities of the iron phosphide catalyst were found to be phase dependent. The lowest electrode potential of 110 mV vs. a reversible hydrogen electrode (RHE) at 10 mA cm−2 was achieved with Fe 2 P/FeP−500 °C catalyst. Image 1 • Iron phosphides catalyst were synthesized via a wet-chemistry method. • Spin-coating of iron phosphide particles onto graphite substrates yielded uniform thin films. • Heat treatment of iron phosphides at 500 °C resulted in structural changes. • The iron phosphide films were used as electrocatalysts for efficient hydrogen evolution. [ABSTRACT FROM AUTHOR]

The reaction of NiCl2, K2(i-mnt) (i-mnt2−= 2,2-dicyanoethylene-1,1-dithiolate) and 1-benzyl-4-amino-pyridinium bromide [BzPyNH2]Br affords a nickel complex, [BzPyNH2]2[Ni(i-mnt)2], a molecular catalyst for electrochemical and photochemical driven hydrogen evolution. As an electrocatalyst, [BzPyNH2]2[Ni(i-mnt)2] can electrocatalyze hydrogen generation from a neutral buffer with a turnover frequency (TOF) of 556 (±3) mol of hydrogen per mole of catalyst per hour (mol H2/mol catalyst/h) at an overpotential (OP) of 837.6 mV. As a photocatalyst, combining with CdS nanorods (CdS NRs) as a photosensitizer, and ascorbic acid (H2A) as a sacrificial electron donor, [BzPyNH2]2[Ni(i-mnt)2] photocatalyzes hydrogen evolution in heterogeneous environments with a turnover number (TON) of 18420 (±5) mol H2 per mol of catalyst during 60 h irradiation. The highest apparent quantum yield (AQY) is ∼10% at 469 nm. Several chemical and physical methods are employed to understand catalytic procedures for H2 production. [ABSTRACT FROM AUTHOR]