Lanthanide sulfide decorated graphene oxide nanorods as an effective photocatalysts for reducing dyes, free radicals, and water split to produce H2 in sunlight

Abstract

Lanthanide sulfide nanorods (LSNR) were synthesized by designing a crash reaction mechanism for reducing crystalline 6 H2O of lanthanoid nitrate (Ln(NO3)3*6H2O) with fine pecies of sodium metal at normal temperature and pressure (NTP) unlike at >800−1300°C. The 6 H2O reduction formed a lanthanide hydroxide (Ln(OH)3), which was treated with hydrogen sulfide (H2S) on passing it in aquesous solution that formed LSNR (Pr2S3, Sm2S3, Eu2S3, and Gd2S3 NRs) settled at bottom. LSNR have doped graphene oxide (GO) as LSNR-GO and used to photodegrade methylene blue (MB) and rhodamine B (RhB) in sunlight (SL) at pH2,7,11, and scavenged 68% 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals at pH-7. Eu2S3-GO and Gd2S3-GO have degraded ∼98% MB and ∼99% RhB within 120 min. LSNR-GO has split water to H2andO2, like Gd2S3-GO has generated 2374 μL H2 in 60 min. The 4f2, 4f5, 4f6, and 4f7 electrons (4f#e) of LSNR-GO respectively have hindered a recombination rate of excited electrons (e−) and holes (h+) of GO functional edges (FE) to 11% higher photocatalytic efficiency. Mutual wavefunctions of FE and 4f#e via Förster resonance energy transfer (FRET) have exchanged their energy levels. LSNR-GO as effective photocatalysts have reduced fluorescent industrial wastes in SL. Carbon atoms of GO with equal energy distribution (2s12px12py12pz1) have doped LSNR due to contraction activities. X-ray diffraction (XRD), thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy illustrated interlinked LSNR-GO sheets with 4f#e orbital, by shortening a reduction time.