Incorporating NiCoP Cocatalyst into Hollow Rings of ZnCo-Metal–Organic Frameworks to Deliver Pt Cocatalyst like Visible Light Driven Hydrogen Evolution Activity

Abstract

In the field of photocatalysis, metal–organic frameworks (MOFs) have emerged as potential photocatalysts owing to their well-defined and tailorable porous structures, high surface areas, and inherent semiconductor-like behavior. However, their photocatalytic H2 evolution reaction is still limited due to the higher charge recombination rates. Precious metal cocatalysts, such as Pt and Au, are used to suppress electron–hole recombination effects by forming a Schottky junction, but the high cost and scarcity of these metals limit their large-scale applications. Herein, for the first time, we have developed novel ZnCo-MOF hollow rings at room temperature and loaded it with monodispersed transition-metal phosphide (TMPs; NiCoP, FeCoP, Ni2P, CoP) nanoparticles as non-noble-metal cocatalysts for efficient visible light driven H2 evolution reaction. The as-obtained NiCoP@ZnCo-MOF composite displays significantly improved H2 production rates as compared to the parent MOF and their physical mixture and offers similar photocatalytic H2 evolution activity as compared to that of Pt@ZnCo-MOF. This is attributed to efficient n–n heterojunction charge separation and transfer, and rapid H2 evolution reaction dynamics by the reduction of activation energy by NiCoP cocatalyst. The H2 production rate of NiCoP@ZnCo-MOF is 8583.4 μmol h–1 g–1, 16 times higher than parent ZCM, and the apparent quantum yield (AQY) is 20.1% at 590 nm, which remained constant for a minimum of 18 h of repeated cycling in the H2 production without any degradation of the catalyst.

Experimental and Computational Insights into the Overall Water Splitting Reaction by the Fe–Co–Ni–P Electrocatalyst

“…The M­(III) states in the XPS spectra indicate the formation of M–*OOH over the other two species. Figure d confirms the formation of M–P bonds, as indicated by the peak at 129.47 eV in the P 2p spectrum . The unresolved peak at 133.38 eV in the P 2p spectrum corresponds to the P–O bonds. , The peak intensity of the M–P bond is decreased and the P–O bond is increased in the spent catalyst, revealing the surface oxidation of the sample.…”

“…48,52 The peaks in Figure 5c at binding energies of 852.87 and 870.7 eV are attributed to the Ni−P bond, indicating the formation of Ni 2 P. 49 The fitted peaks observed at 855.67 and 857.00 eV are for Ni 2p 3/2 and 874.03 eV for Ni 2p 1/2 , revealing the surface-oxidized Ni(II)/Ni(III) followed by two satellite peaks at 861.46 and 879.58 eV. 49,52 It is noteworthy that the spin−orbit peaks of M 2p 3/2 and M 2p 1/2 for all three metal ions display a minor shift toward higher binding energies when compared to the reported values and standards. This shift is attributed to the displacement of the M electron cloud caused by P, where the later one has a higher electronegativity.…”

High performance of visible-light driven hydrogen production over graphdiyne (g-CnH2n−2)/MOF S-scheme heterojunction

“…It is understood that ZIFs are used as a precursor for preparing porous carbon materials, which can efficiently transfer their morphology and pore structure to carbon materials, and achieve the uniform doping of various atoms. 30–35…”

“…It is understood that ZIFs are used as a precursor for preparing porous carbon materials, which can efficiently transfer their morphology and pore structure to carbon materials, and achieve the uniform doping of various atoms. [30][31][32][33][34][35] Carbon-based materials are widely studied because of their characteristic π-conjugated skeleton. [36][37][38][39][40][41][42] By adjusting the proportion and changing the hybrid category, carbon allotropes with different categories, dimensions and properties can be constructed.…”

Interfacial‐Engineered Co3S4/MnCdS Heterostructure for Efficient Photocatalytic Hydrogen Evolution

“…Compared with the single component catalyst, composites usually displayed special functions. [ 7 ] Therefore, several effective strategies such as constructing heterostructures [ 8 ] and cocatalyst modifications [ 9 ] have been employed to further improve the activity and stability of solid solutions. For example, by constructing a novel all‐solid‐state 0D/2D direct Z‐scheme heterojunction of Mn 0.2 Cd 0.8 S/CeO 2 , the hydrogen evolution rate of CeO 2 was improved by about 119 times (8.73 mmol h −1 g −1 ) in an aqueous solution including Na 2 S/Na 2 SO 3 [8a] .…”