Metal‐Organic Framework Templated Synthesis ofg‐C₃N₄/Fe₂O₃@FeP Composites for Enhanced Hydrogen Production

Abstract

The simultaneous construction of heterostructures and co‐catalyst loading while maintaining a tight contact favoring charge transfer is important for improving the photocatalytic H2 production of g‐C3N4. Following this approach, we prepared herein a Fe2O3@FeP hybrid material by annealing and phosphidation of a g‐C3N4/Fe metal‐organic framework (MOF). The as‐prepared Fe2O3@FeP was used as both heterojunction and co‐catalyst material to enhance the photocatalytic H2 evolution performance of g‐C3N4 by water splitting under visible‐light irradiation. We developed an optimized g‐C3N4/Fe2O3@FeP‐60 catalyst with a H2 evolution rate as high as 12.03 mmol g−1 h−1 under Eosin Y (EY, 1.0 mmol L−1)‐sensitization. This rate was 12 times higher than that of pristine EY‐sensitized g‐C3N4 (0.97 mmol g−1 h−1). The apparent quantum efficiency (AQE) at 420 nm was 38.8 %. The improved photocatalytic activity of this composite compared to g‐C3N4 can be ascribed to: (i) its enhanced visible‐light absorption intensity; (ii) its efficient electron‐hole separation by the formation of a type‐II heterojunction with Fe2O3 and the loading of an electron collector such as FeP; and (iii) the accelerated H+ reductive reaction resulting from the FeP co‐catalyst. We believe that this work may pave the way for the construction of MOF‐based hybrid H2‐evolution photocatalysts.

Cu3P and Ni2P co‐modified g‐C3N4 nanosheet with excellent photocatalytic H2 evolution activities

“…4) further confirms that Cu, Ni and P were successfully anchored on g‐C 3 N 4 . In addition, it reveals the intimate contact between Cu 3 P and Ni 2 P with g‐C 3 N 4 , which likely facilitated photogenerated electron transport and separation 62 …”

α−Fe2O3 Nanoparticles/Porous g−C3N4 Hybrids Synthesized by Calcinations of Fe‐based MOF/Melamine Mixtures for Boosting Visible‐Light Photocatalytic Tetracycline Degradation

“…As the Fe 2 O 3 /g−C 3 N 4 ‐0.4 exhibited the best photocatalytic activity, its morphology and structure was further characterized as a representation of Fe 2 O 3 /g−C 3 N 4 hybrids. The SEM image (Figure a) shows that the Fe 2 O 3 particles possess a rod‐like shape with the length of 1–2 μm and diameter of 200–300 nm, which partially preserve the morphology of MIL‐101 (Fe) . Figure b reflects that the g−C 3 N 4 derived from melamine seems like bulk material.…”

“…Nevertheless, the short lifetime of photo‐generated charge carriers and small hole diffusion length greatly hinder the widespread application of α−Fe 2 O 3 in photocatalysis . In the past several years, the coupling of g−C 3 N 4 with α−Fe 2 O 3 has been an effective route to enhance themselves′ visible‐light photocatalytic activity in various fields such as pollutant degradation, hydrogen production, CO 2 reduction, organic synthesis, and nitrogen fixation . Due to the appropriate band positions of α−Fe 2 O 3 and g−C 3 N 4 , the strong interfacial coupling of α−Fe 2 O 3 /g−C 3 N 4 hybrids largely promoted the transfer and separation of photoinduced charge carriers by common or even Z‐scheme modes, directly accounting for their high photocatalytic efficiency.…”

“…Due to the appropriate band positions of α−Fe 2 O 3 and g−C 3 N 4 , the strong interfacial coupling of α−Fe 2 O 3 /g−C 3 N 4 hybrids largely promoted the transfer and separation of photoinduced charge carriers by common or even Z‐scheme modes, directly accounting for their high photocatalytic efficiency. Recently, some α−Fe 2 O 3 /g−C 3 N 4 hybrids were prepared by calcinations of Fe‐based metal‐organic frameworks (MOFs) and g−C 3 N 4 or Fe‐based MOFs and precursors of g−C 3 N 4 . The use of Fe‐based MOFs were beneficial to the regulation of α−Fe 2 O 3 with nanostructures, formation of strong interfacial coupling with g−C 3 N 4 , and enhancement of specific surface area of hybrids, and hence these hybrids exhibited particularly high photocatalytic activity for hydrogen production and pollutant degradation.…”

Transition‐Metal‐Based Cocatalysts for Photocatalytic Water Splitting

“…CoP Calcination λ > 420 nm (Xe) Na 2 SþNa 2 SO 3 13785 (H 2 ) 11.6 (420 nm) (2018) [206] Zn 0.5 Cd 0.5 S CoP Impregnation AM 1.5G (Xe) Ascorbic acid 12175.8 (H 2 ) 45 (365 nm) (2018) [207] CdS Fe 2 P Impregnation λ ≥ 420 nm (Xe) Ethanol 220000 (H 2 ) 90 (420 nm) 180 (2018) [208] g-C 3 N 4 Fe 2 P Impregnation λ > 420 nm (Xe) TEOA 214 (H 2 ) -(2018) [209] g-C 3 N 4 MoP Impregnation λ > 400 nm (Xe) TEOA 327.5 (H 2 ) 9.6 (400 nm) (2018) [210] CaIn 2 S 4 Ni 2 P Impregnation λ > 400 nm (Xe) Lactic acid 486 (H 2 ) -(2018) [211] CdS Ni 2 P Hydrothermal-calcination λ > 420 nm (Xe) Na 2 SþNa 2 SO 3 34900 (H 2 ) 21.7 (2018) [212] g-C 3 N 4 Ni 2 P Impregnation λ > 420 nm (Xe) TEOA 474.7 (H 2 ) 3.2 (435 nm) (2018) [213] g-C 3 N 4 Ni 2 P Hydrothermal AM 1.5 (Xe) TEOA 3344 (H 2 ) 9.1 (420 nm) (2018) [214] OH-GQDs Ni 2 P Impregnation λ > 420 nm (Xe) TEOA 1566.7 (H 2 ) 0.46 (420 nm) (2018) [215] MIL-125-NH 2 Ni 2 P Impregnation λ ≥ 420 nm (Xe) TEOA 894 (H 2 ) 27 (400 nm) (2018) [216] Zn 0.5 Cd 0.5 S N i 2 P Hydrothermal (Xe) Na 2 SþNa 2 SO 3 23460 (H 2 ) 18.1 (420 nm) (2018) [217] ZnIn 2 S 4 Ni 2 P Impregnation λ > 400 nm (Xe) Lactic acid 2066 (H 2 ) 7.7 (420 nm) (2018) [59a] g-C 3 N 4 CoP Calcination λ > 420 nm (Xe) TEOA 1074(H 2 ) 6.1 (420 nm) (2019) [218] g-C 3 N 4 Cu 3 P Impregnation-Calcination λ > 420 nm (Xe) TEOA 808 (H 2 ) -(2019) [219] g-C 3 N 4 Fe 2 O 3 @FeP Calcination λ ≥ 420 nm (Xe) TEOA 12030 (H 2 ) 38.8 (420 nm) (2019) [220] g-C 3 N 4 FeP Calcination λ > 420 nm (Xe) TEOA 177.9 (H 2 ) 1.57 (420 nm) 9 (2019) [221] g-C 3 N 4 MoP Impregnation-calcination AM 1.5G (Xe) TEOA 807.6 (H 2 ) 18.3 (420 nm) (2019) [222] g-C 3 N 4 Ni 2 P Impregnation λ > 400 nm (Xe) TEOA 2337.09 (H 2 ) 3.98 (420 nm) (2019) [223] CdS-DETA Ni 2 P Grinding λ > 420 nm (Xe) Na 2 SþNa 2 SO 3 6836 (H 2 ) 26.4 (400 nm) (2019) [224] CN x Ni 2 P Calcination AM 1.5 (Xe) Poly(lactic acid) 3.6 (H 2 ) 0.035 (430 nm) 120 (2019) [225] 2.51 (420 nm) (2019) [226] g-C 3 N 4 Ni-P Electroless-plating AM 1.5 (Xe) TEOA 1051 (H 2 ) 5 (2019) [227] CdS(PD) SC-WP Impregnation 420 nm (LED) Lactic acid 15446.21 (H 2 ) 12.8 (475 nm) > 25 (2019) [228] g-C 3 N 4 Ni 2 P Impregnation (Xe) TEOA 205 (H 2 ) --(2019) [229]…”