Platinum deposition onto g-C3N4 with using of labile nitratocomplex for generation of the highly active hydrogen evolution photocatalysts

Abstract

The chemisorption of the labile dimeric platinum nitratocomplex [Pt 2 (μ-OH) 2 (NO 3 ) 8 ] 2- onto graphene oxide doped graphitic C 3 N 4 (g–C 3 N 4 –GO) was performed for the first time to prepare PtO x /g–C 3 N 4 –GO composites with ionic platinum species (Pt(II)) bonded with N-donor groups of the g-C 3 N 4 . The thermal treatment of the obtained composites in the hydrogen atmosphere results in a gradual reduction of Pt(II) species with the formation of Pt/g–C 3 N 4 –GO photocatalysts. The Pt/g–C 3 N 4 –GO catalysts paired with TEOA sacrificing agent in an aqueous solution were tested in a photoinduced hydrogen evolution reaction under visible light (λ = 425 nm). The photocatalytic activity of prepared materials strongly influenced by the temperature of the reduction stage so that the maximal rate of H 2 evolution was revealed for the catalyst (0.5 wt% of Pt) reduced at 400 °C with a quantum efficiency of 3.0% and rate of HER of 5.1 mmol h −1 per 1 g of photocatalysts. The photocatalytic activity of this sample was much higher than the activity of 0.5% Pt/g–C 3 N 4 –GO photocatalysts prepared by conventional photoreduction of H 2 PtCl 6 or reduction of this precursor with NaBH 4 . The Pt/g–C 3 N 4 –GO photocatalyst with Pt concentration of 0.1 wt% was prepared using the described protocol and shown specific activity of about 1.4 mol h −1 per 1 g of Pt outperforming analogous material reported to date. • PtO x /g–C 3 N 4 –GO composites were obtained using dimeric platinum(IV) nitratocomplex. • Thermal treatment at 100–400 °C in H 2 results in the formation of Pt/g–C 3 N 4 –GO catalysts. • Activity was tested in H 2 evolution from triethanolamine water solution (λ = 425 nm). • Highest activity (5.1 mmol g −1 h −1 ) was achieved by photocatalyst reduced at 400 °C. • 0.1% Pt/g–C 3 N 4 –GO (400 °C) achieved specific activity of 1.4 mol h −1 per 1 g of Pt.