Co₂P Nanorods as an Efficient Cocatalyst Decorated Porous g‐C₃N₄ Nanosheets for Photocatalytic Hydrogen Production under Visible Light Irradiation

Abstract

promote the photocatalytic activity for H 2 generation. [4] Up to now, transition metal sulfides, namely NiS, [5,6] MoS 2 , [7,8] and WS 2 , [9,10] generally act as noble metal-free cocatalysts modified g-C 3 N 4 for the achievement of enhanced photocatalytic H 2 evolution activity. In analogy to metal sulfides, transition metal phosphides such as Ni 2 P, [11] Ni 12 P 5 , [12,13] and CoP, [14] also serve as reduction cocatalysts decorated g-C 3 N 4 for light-driven H 2 evolution. However, nearly all the reported metal phosphides loaded g-C 3 N 4 are synthesized via a gassolid reaction strategy using NaH 2 PO 2 or NH 4 H 2 PO 4 as P sources, in which the synthesis undergoes multistep procedures and high temperature for releasing highly toxic PH 3 from hypophosphites. [15] Furthermore, the as-developed metal phosphide/g-C 3 N 4 systems often consist of 0D nanoparticles and g-C 3 N 4 . To the best of our knowledge, other dimensions of metal phosphides such as 1D nanorods and 2D nanosheets have not ever been reported hitherto for the g-C 3 N 4 -based photocatalytic system for H 2 production.Recently, Co 2 P has been widely used in the fields of supercapacitors, [16] lithium ion batteries, [17] and electrocatalytic H 2 evolution reaction. [18] Not only that, 0D Co 2 P nanoparticles have also been employed as efficient cocatalysts integrated CdS nanorods for photocatalytic H 2 evolution. [19] Lu and co-workers also accentuated that Co 2 P was a promising and highly efficient candidate as a cocatalyst for photocatalytic H 2 evolution reaction. [20] Nevertheless, at present, the 1D Co 2 P nanorods are scarcely discussed as cocatalysts for H 2 photogeneration. Equally important, it constitutes a critical challenge for the hybridization of 1D Co 2 P nanorods and 2D g-C 3 N 4 nanosheets.Here, we report a novel type of hybrid photocatalysts composed of 1D metal phosphides and 2D g-C 3 N 4 nanosheets, which feature relatively low-cost, a facile preparation, and noble metal-free photocatalytic H 2 evolution. Briefly, the colloidally synthesized Co 2 P nanorods by using low-cost triphenylphosphine (TPP) as the P source were successfully loaded on the porous g-C 3 N 4 nanosheets for the first time through a solutionphase route under sonication. In this work, the cocatalysts of Co 2 P nanorods play an imperative role in the photocatalytic H 2 generation, which could be attested by photoluminescence (PL) spectroscopy and photoelectrochemical (PEC) analysis. Essentially, this solution-phase approach could be broadly applied for the rational construction of other 1D and 2D nanomaterials, C 3 N 4 ), which typically acts as the 2D support for loading with cocatalysts, endows fascinating performances for photocatalytic water splitting. Benefiting from the natural sheet-like structure in g-C 3 N 4 , 1D metal phosphides (Co 2 P) nanorods are incorporated into 2D porous g-C 3 N 4 nanosheets via a solution-phase method under ultrasonication. The novel 1D/2D Co 2 P/g-C 3 N 4 heterojunction nanohybrids exhibit ameliorated visible-light phot...

DFT Study on the Hydrogen Evolution Reaction for Different Facets of Co2P

“…In particular, the transition metal phosphides (TMPs) have been proved to have both high stability and high activity like MoP,, FeP/FeP 2 ,, CoP/Co 2 P, and Ni 2 P ,. Among numerous TMPs developed, the Co−P compounds, which are non‐noble metal catalysts, have attracted extensive interest in the field of HER catalysis in the past years, owing to their good performance, such as high activity,, outstanding stability both in acidic electrolytes,, and alkaline solutions,, high conductivity, large‐scaled production and so on. So far, there are two major Co−P components explored experimentally as CoP and Co 2 P. Callejas et al .…”

“…Although lots of experiments have been done about Co 2 P, the facet‐dependent HER activity of Co 2 P has not been systemically studied experimentally or theoretically, which is important to understand the facet effects on HER activity for Co 2 P. In this paper, DFT calculations for different adsorption sites on several facets of Co 2 P have been performed to investigate the facet‐dependent HER activity of Co 2 P. Beyond that, multiple linear regression has been applied to quantitatively analyze the relationship between the local structures and the corresponding Gibbs free energy of H* (ΔG H* ). The mathematical model of multiple linear regression is helpful in understanding the facet impact on HER activity and finding out the facet with best HER activity.…”

Functionalized Hybridization of 2D Nanomaterials

“…[21] As reported, thiol ligand modifications can readily occur on both internal and perimeter edges of MoS 2 nanosheets due to their higher molecular III: Hybridization of protons and semiconductor nanostructures on g-C 3 N 4 nanosheets g-C 3 N 4 Protons Sonication-driven exfoliation of g-C 3 N 4 in 10 m HCl Biosensor New heparin sensing platform with a detection limit of 18 ng mL −1 [163] g-C 3 N 4 Co 2 P nanorods Sonication-driven embedding of Co 2 P nanorods into g-C 3 N 4 nanosheets HER High H 2 production rate at 53.3 µmol g −1 h −1 (no H 2 evolution observed by using g-C 3 N 4 alone) [170] Li + battery Reversible capacity of 800 mA h g −1 at a current density of 100 mA g −1 , and no capacity drop over 500 charge/discharge cycles at a current density of 400 mA g −1 [240] affinities. [21] As reported, thiol ligand modifications can readily occur on both internal and perimeter edges of MoS 2 nanosheets due to their higher molecular III: Hybridization of protons and semiconductor nanostructures on g-C 3 N 4 nanosheets g-C 3 N 4 Protons Sonication-driven exfoliation of g-C 3 N 4 in 10 m HCl Biosensor New heparin sensing platform with a detection limit of 18 ng mL −1 [163] g-C 3 N 4 Co 2 P nanorods Sonication-driven embedding of Co 2 P nanorods into g-C 3 N 4 nanosheets HER High H 2 production rate at 53.3 µmol g −1 h −1 (no H 2 evolution observed by using g-C 3 N 4 alone) [170] Li + battery Reversible capacity of 800 mA h g −1 at a current density of 100 mA g −1 , and no capacity drop over 500 charge/discharge cycles at a current density of 400 mA g −1 [240] affinities.…”

“…[167] The formed phosphorus-carbon bonds resulted in an effective interfacial charge separation between the two components to exhibit a high HER rate at 271 µmol h −1 g −1 , which is 5.6 and 4.2 times greater compared with pristine g-C 3 N 4 nanosheets and black phosphorus dots, respectively. [170] Meanwhile, BiPO 4 nanorods were immobilized at the surface of g-C 3 N 4 nanosheets through a strong electrostatic interaction to effectively degrade Rhodamine B (94.3% within 6 min under UV light irradiation), which was ≈4.2 times and ≈1.5 times higher than that of BiPO 4 and g-C 3 N 4 , respectively. [168] In Song's work, g-C 3 N 4 nanosheets were obtained through thermal exploitation of g-C 3 N 4 bulk followed by loading with Ag 2 CO 3 nanoparticles to show excellent photocatalytic activity due to an increased specific surface area and enhanced charge separation rate.…”

Fabrication of TiO2/high‐crystalline g‐C3N4 composite with enhanced visible‐light photocatalytic performance for tetracycline degradation

“…For the BCN and HCCN, the absorption peak at 808 cm −1 corresponded to the mode of vibration of heptazine units. 26,27 The absorption bands between 1200 and 1700 cm −1 denote the stretching vibration modes of C─N and C═N. 28,29 Another wide absorption band between 3000 and 3650 cm −1 is the result of the stretching vibration of terminal ─NH groups.…”