2D Carbon Nitride Research Articles

High density cobalt single atom catalysts for H2O2 electrosynthesis: A critical design of carbon nitride skeleton

Direct hydrogen peroxide (H2O2) electrosynthesis via the two-electron oxygen reduction reaction (ORR) provides aburgeoning alternative to the industrial anthraquinone process.In this work, based on first-principles calculations and a targeted structural search, we predicted a new two-dimensional (2D) carbon nitride monolayer, PH-CN, accompanied by high mechanical stability and adequate intrinsic pyrrolic N-rich network, such remarkable merits ensure its greatpotential as substrates. Herein, we demonstrate how the coordination environment regulates the electronic structure of the Co central atom and thus steers the ORR selectivity and activity using a series of control samples based on the most prevalent CoN4 moiety. As expected, the acquired P-CoN4 and PH-CoN4 show excellent H2O2electrosynthesis performance with low thermodynamic overpotential of 0.02 and 0.07 V, as well as extremely high Co loadings of 26.28 and 27.42 wt%, respectively. This work sheds light on how the carbon nitride skeleton affects catalytic activities on Co-N-C catalysts.

Two-dimensional tetragonal carbon nitride semiconductors with fascinating electronic/optical properties and low thermal conductivity

Abstract Exploring two-dimensional (2D) tetragonal carbon nitride materials is significant for unlocking new physical properties beyond those offered by traditional hexagonal lattices. In this work, we propose three theoretically stable 2D carbon nitride monolayers with tetragonal lattices, namely T-C3N, P-C3N, and PH-C5N4. Electronic structure calculations indicate that all three monolayers exhibit semiconducting characteristics, with T-C3N showing interesting flat band features. Additionally, these three carbon nitrides exhibit anisotropic and high carrier mobilities and excellent light absorption capabilities in the visible-light and near-infrared regions. Meanwhile, the calculated thermal conductivity (κp) of PH-C5N4 is 63.9 Wm−1K−1 at room temperature, significantly outperforming T-C3N (12.2 Wm−1K−1) and P-C3N (18.9 Wm−1K−1). Phonon scattering rates and Grüneisen parameters confirm the origin for the relatively high κp in PH-C5N4. Our study proposes three tetragonal carbon nitride structures with novel physical properties, which lays a theoretical foundation for the multifunctional applications of 2D carbon nitride materials.

Single-metal-adatom catalysts for the synthesis of 2D carbon nitride metal-coordinated networks

Metal-coordinated networks have been found to be excellent catalyst for environmental purposes, such as green hydrogen generation or photo-degradation of pollutants. Recently, its traditional three-dimensional structure has been extended to two dimensions. However, the synthesis and stability of these networks in their 2D form remains a challenge. We have designed, characterized and synthesized, using a bottom-up approach, a 2D metal-coordinated network combining melamine molecules and thermally generated native copper adatoms on a Cu(110) substrate at 600 K. As a result, we have obtained a 2D hexagonal carbon nitride Cu-coordinated network. We demonstrate that the underlying mechanism of its formation involves partial dehydrogenation and subsequent metalation of amino groups. We prove the crucial role of copper adatoms in the formation, serving as heterogeneous metal-site catalysts, as well as in the further stabilization of the network. The obtained metal-coordinated network is indeed a single atom catalyst with high potential in technological applications.

Synergistic Modulation of π-π* and n-π* Transitions by In Situ Phenol-Like Structure Integration for Efficiently Wide-Spectrum Hydrogen Production of Ultrathin Carbon Nitride.

2D carbon nitride nanosheets, exemplified by g-C3N4, offers significant structural benefits and enhanced photocatalytic activity. Nonetheless, the quantum confinement effect prevalent in nanoscale photocatalysts would result in an enlarged bandgap, potentially restricting the spectral absorption range and impeding improvements in photocatalytic efficiency. Here, a high-performance 2D photocatalyst with an extended spectral response is achieved by incorporating a novel phenol-like structure into the conjugated framework of ultrathin g-C3N4 nanosheet. This novel strategy features targeted pyrimidine doping to create a conjugated carbon zone in heptazine structure, offering a thermodynamically favorable pathway for hydroxyl functionalization during the annealing exfoliation process. Consequently, the π-π* transition energy in the material is significantly decreased, and the active lone pair electrons in phenol-like structure induces a new n-π* transition with notably enhanced absorption from 500 to 650nm. The optimized material shows a dramatic enhancement in photocatalytic activity, achieving ≈72 times than the activity of bulk g-C3N4, and demonstrating a measurable H2 production rate of 6.57µmol g-1 h-1 under 650nm light. This study represents a significant step forward in the strategic design of 2D photocatalysts, with tailored electronic structures that significantly boost light absorption and photocatalytic efficiency.

Enhanced Electron Delocalization Induced by Ferromagnetic Sulfur doped C3N4 Triggers Selective H2O2 Production.

For the 2D metal-free carbon catalysts, the atomic coplanar architecture enables a large number of pz orbitals to overlap laterally, thus forming π-electron delocalization, and the delocalization degree of the central atom dominates the catalytic activity. Herein, designing sulfur-doped defect-rich graphitic carbon nitride (S-Nv-C3N4) materials as a model, we propose a strategy to promote localized electron polarization by enhancing the ferromagnetism of ultra-thin 2D carbon nitride nanosheets. The introduction of sulfur (S) further promotes localized ferromagnetic coupling, thereby inducing long-range ferromagnetic ordering and accelerating the electron interface transport. Meanwhile, the hybridization of sulfur atoms breaks the symmetry and integrity of the unit structure, promotes electron enrichment and stimulating electron delocalization at the active site. This optimization enhances the *OOH desorption, providing a favorable kinetic pathway for the production of hydrogen peroxide (H2O2). Consequently, S-Nv-C3N4 exhibits high selectivity (>95 %) and achieves a superb H2O2 production rate, approaching 4374.8 ppm during continuous electrolysis over 300 hour. According to theoretical calculation and in situ spectroscopy, the ortho-S configuration can provide ferromagnetic perturbation in carbon active centers, leading to the electron delocalization, which optimizes the OOH* adsorption during the catalytic process.

Manipulating interface-induced multi-channel charge transfers toward highly hierarchical synchronous g-C3N4/STO@Pt modulation for boosting artificial photosynthesis

For the transformation of energy conversion and photocatalytic decomposition, photocatalyst-based artificial photosynthesis for solar-to green fuels and environmental treatment has aroused great attention. Herein, a novel ternary heterojunction based on constructing an interaction between 2D-graphitic carbon nitride (CN), 3D-strontium titanate (STO) and Pt nanoparticles (NPs) (2D/3D CN/STO@Pt) is designed for the first time to greatly promote photocatalytic water cracking hydrogen (H2) evolution in an alkalescent environment, such as triethanolamine (TEO) as well as integrating with Rhodamin B (RhB) decomposition. Under optimized conditions, the H2 productivity over 3D/2D CN/STO@Pt-3 heterostructures (10,005 μmol h−1 g−1) with an apparent quantum yield of H2 production approaching 47.5% is found to be ∼29.7, 8.5, 1.1, and 1.5-fold as much as that in the CN, CN/STO, CN/STO@Pt-1, and CN/STO@Pt-5 heterojunctions, respectively. An up to 2.5-fold enhancement in the photocatalytic RhB decomposition rate, obtaining 90% within 60 min under visible-light-driven is observed for 3D/2D CN/STO@Pt-3 heterostructures, surpassing that of other samples. The CN/STO@Pt-3 sample shows the highest degradation rate of 3.5 min−1, which is 1.8, 2.8, 4.27 and 4.9 -time higher than that of the CN/STO@Pt-1, CN/STO@Pt-5, CN, and STO samples, respectively. The improved photocatalytic behavior of the heterogeneous structures could be ascribed to i) the type II-heterojunction between 2D CN and 3D STO; and ii) the creation of the Schottky contacts between semiconductors and Pt NPs. The configuration of the type-II heterojunction formed by the two semiconductors of 2D g-C3N4 and 3D STO contributes to improved light absorption ability, and rapid separation and transfer of photoinduced charges. At the same time, the close junction of Pt establishes the Schottky barrier to facilitate efficient electron transfer in the ternary nanostructures, impeding the quick recombination of photoexcited charge carriers, and offering abundant reactive sites, contributing multiple electron pathways for the photoreaction strategy. Increased photocurrent density from the LSV measurement and a declined in PL intensity confirmed the enhanced interfacial charge separation in the tertiary photocatalyst. Furthermore, the CN/STO@Pt-3 ternary heterostructure presents outstanding photocatalytic performance after five cycles, indicating good stability and reusability. This work gives a valuable modification pathway for the establishing multi-channel charge carrier transport for energy conversion and environmental remediation processes.

Prediction of two-dimensional carbon nitride materials with semimetal states and flat bands

The search for new two-dimensional (2D) carbon nitride (CN) materials with desirable properties is an important and critical area of research. This study presents a series of 2D CN materials with appealing features such as semimetal or flat bands. By utilizing group theory and graph theory, we perform a random search of the configurational space of 2D CN monolayers, leading to the identification of 721 new CN materials. Extensive density functional theory calculations were then conducted to evaluate their properties. We found that 57 materials exhibit semimetal behavior, while 664 display characteristics of semiconductors and normal metals. Notably, materials such as 51-5-16-C3N-r568 and 55-5-20-C4N-r568 feature topological Dirac semimetals with protected 1D topological boundary states. Moreover, 31 materials possess flat bands near their Fermi level, including two with kagome-like flat bands that induce intrinsic spontaneous magnetization due to partially-occupied flat bands. Our results offer several promising candidates for exploring physical phenomena related to semimetals or flat bands in 2D CN materials.

Enhanced Electron Delocalization Induced by Ferromagnetic Sulfur doped C 3 N 4 Triggers Selective H 2 O 2 Production

For the 2D metal‐free carbon catalysts, the atomic coplanar architecture enables a large number of pz orbitals to overlap laterally, thus forming π‐electron delocalization, and the delocalization degree of the central atom dominates the catalytic activity. Herein, designing sulfur‐doped defect‐rich graphitic carbon nitride (S‐Nv‐C3N4) materials as a model, we propose a strategy to promote localized electron polarization by enhancing the ferromagnetism of ultra‐thin 2D carbon nitride nanosheets. The introduction of sulfur (S) further promotes localized ferromagnetic coupling, thereby inducing long‐range ferromagnetic ordering and accelerating the electron interface transport. Meanwhile, the hybridization of sulfur atoms breaks the symmetry and integrity of the unit structure, promotes electron enrichment and stimulating electron delocalization at the active site. This optimization enhances the *OOH desorption, providing a favorable kinetic pathway for the production of hydrogen peroxide (H2O2). Consequently, S‐Nv‐C3N4 exhibits high selectivity (>95%) and achieves a superb H2O2 production rate, approaching 4374.8 ppm during continuous electrolysis over 300‐hour. According to theoretical calculation and in‐situ spectroscopy, the ortho‐S configuration can provide ferromagnetic perturbation in carbon active centers, leading to the electron delocalization, which optimizes the OOH* adsorption during the catalytic process.

Semimetallic state transition in Two-Dimensional carbon nitride covalent networks and enhanced electrocatalytic activity for nitrate to ammonia conversion

Single-atom catalysts (SACs), due to their maximum atomic utilization rate, show tremendous potential for application in the electrocatalytic synthesis of ammonia from nitrate. Yet, the development of superior supports that preserve the high selectivity, activity, and stability of SACs remains an imperative challenge. In this work, based on first-principles calculations and tight-binding (TB) model analysis, a new two-dimensional (2D) carbon nitride monolayer, C7N6, is proposed. The C7N6 structure exhibits a strong covalent network, with dynamical, thermal, and mechanical stability. Surprisingly, the structural transition from C9N4 to C7N6 corresponds to a semimetallic state transition. Further symmetry analysis unveils that the Dirac states in C7N6 are protected by space–time inversion symmetry, and the physical origin of the Dirac cone was confirmed using the TB model. Additionally, a non-zero Z2 invariant and significant topological edge states demonstrate its topologically nontrivial nature. Considering the excellent structural and topological properties of C7N6, a three-step screening strategy is designed to identify eligible SACs for electrochemical nitrate reduction reaction (NO3RR), and Ti@C7N6 is identified as possessing the best activity, with the last proton-electron coupling step *NH2→*NH3 being the potential-determining step (PDS), for which the limiting potential is 0.48 V. Moreover, a free energy diagram shows that the *NOH reaction pathway is energetically preferred on Ti@C7N6, and ab initio molecular dynamics (AIMD) calculations at 500 K confirm its good thermal stability. Our study not only provides excellent CN-based support material but also offers theoretical guidance for constructing highly active and selective SACs for nitrate reduction.

Enhancing Visible-Light Absorption of 2D Carbon Nitride by Constructing 2D/2D van der Waals Heterojunctions of Carbon Nitride/Nitrogen-Superdoped Graphene.

Carbon nitride sheets (CNs) down to the two-dimensional (2D) limit have been widely used in photoelectric conversion due to their inherent band gap and extremely short charge-carrier diffusion distance. However, the utilization of visible light remains low due to the rapid recombination of photogenerated electron-hole pairs and enlarged band gap. Here, atomically thin 2D/2D van der Waals heterojunctions (vdWHs) of N-superdoped graphene (NG) and CNs (CNs/NG) are fabricated via a facile electrostatic self-assembly method. Our results revealed that the vdWHs can increase the visible-light absorption of CNs by extending the absorption edge from 455 to up to 490 nm. The recombination of photogenerated electron-hole pairs is inhibited because superdoped N in CNs/NG facilitates the transmission of photogenerated carriers in the melon chain. This study opens a new avenue for narrowing the band gap and promoting photoexcited carrier separation in carbon-nitride-based materials.

Cooperative Copper Single-Atom Catalyst in 2D Carbon Nitride for Enhanced CO2 Electrolysis to Methane.

Renewable-electricity-powered carbon dioxide (CO2) reduction (eCO2R) to high-value fuels like methane (CH4) holds the potential to close the carbon cycle at meaningful scales. However, this kinetically staggered 8-electron multistep reduction suffers from inadequate catalytic efficiency and current density. Atomic Cu-structures can boost eCO2R-to-CH4 selectivity due to enhanced intermediate binding energies (BEs) resulting from favorably shifted d-band centers. In this work, 2D carbon nitride (CN) matrices, viz. Na-polyheptazine (PHI) and Li-polytriazine imides (PTI), are exploited to host Cu-N2 type single-atom sites with high density (≈1.5 at%), via a facile metal-ion exchange process. Optimized Cu loading in nanocrystalline Cu-PTI maximizes eCO2R-to-CH4 performance with Faradaic efficiency (FECH4) of ≈68% and a high partial current density of 348mA cm-2 at -0.84V vs reversible hydrogen electrode (RHE), surpassing the state-of-the-art catalysts. Multi-Cu substituted N-appended nanopores in the CN frameworks yield thermodynamically stable quasi-dual/triple sites with large interatomic distances dictated by the pore dimensions. First-principles calculations elucidate the relative Cu-CN cooperative effects between the matrices and how the Cu local environment dictates the adsorbate BEs, density of states, and CO2-to-CH4 energy profile landscape. The 9N pores in Cu-PTI yield cooperative Cu-Cu sites that synergistically enhance the kinetics of the rate-limiting steps in the eCO2R-to-CH4 pathway.

Strong mechanical anisotropy and an anisotropic Dirac state in 2D C5N3.

Two-dimensional (2D) carbon nitride materials have emerged as a versatile platform for the design of high-performance nanoelectronics, but strong anisotropy in 2D carbon nitrides has rarely been reported. In this work, a 2D carbon nitride with strong anisotropy composed of tetra-, penta-, and hexa-rings (named as TPH-C5N3) is proposed. This TPH-C5N3 exhibits both dynamical and mechanical stability. Furthermore, it also showcases remarkable thermal stability, reaching up to 2300 K, as evidenced by AIMD simulations conducted in an NVT environment utilizing the Nosé-Hoover thermostat. Significantly, TPH-C5N3 demonstrates high anisotropic ratios in its mechanical properties, positioning it as the frontrunner in the current carbon nitride systems. In addition, a Dirac cone with an anisotropic ratio of 55.8% and Fermi velocity of 7.26 × 105 m s-1 is revealed in TPH-C5N3. The nontrivial topological properties of TPH-C5N3 are demonstrated by a non-zero Z2 invariant and topologically protected edge states. Our study offers theoretical insights into an anisotropic 2D carbon nitride material, laying the groundwork for its design and synthesis.

Prediction of two-dimensional C3N2 semiconductors with outstanding stability, moderate band gaps, and high carrier mobility.

Two-dimensional (2D) semiconductors with suitable band gaps, high carrier mobility, and environmental stability are crucial for applications in the next generation of electronics and optoelectronics. However, current candidate materials each have one or more issues. In this work, two novel C3N2 monolayers, P-C3N2 and I-C3N2 are proposed by first-principles calculations. Both structures have demonstrated excellent dynamical and mechanical stability, with thermal stability approaching 3000 K. Importantly, P-C3N2 shows a distinct advantage in formation energy compared to currently synthesized 2D carbon nitride materials, indicating its potential for experimental synthesis. Electronic structure calculations reveal that both P-C3N2 and I-C3N2 are intrinsic semiconductors with moderate band gaps of 2.19 and 1.81 eV, respectively. Additionally, both C3N2 monolayers display high absorption coefficients up to 105 cm-1, with P-C3N2 showing significant absorption capabilities in the visible light region. Remarkably, P-C3N2 possesses an ultra-high carrier mobility of up to 104 cm2 V-1 s-1. These findings provide theoretical insights and candidates for future applications in the electronics and optoelectronics fields.

A universal descriptor for two-dimensional carbon nitride-based single-atom electrocatalysts towards the nitrogen reduction reaction

A universal descriptor was constructed by combining DFT calculations and machine learning to predict highly active NRR electrocatalysts based on transition metal atom anchored 2D carbon nitrides with varied C/N ratios (TM@CNx).

Maximizing charge dynamics in ZnIn2S4/CN Van der Waals heterojunction for optimal hydrogen production from photoreforming of glucose

Biomass photoreforming stands out as a promising avenue for green hydrogen, leveraging solar energy for the generation and transformation of clean and renewable energy resources. The pursuit of efficient photocatalysts is motivated by the unsatisfied hydrogen evolution performance arising from the complex and stubborn structure of biomass. Herein, we loaded 2-dimensional (2D) ZnIn2S4 onto 2D carbon nitride nanosheets, resulting in the formation of Van der Waals (VDW) heterojunctions (ZIS/CN). Band structure and morphology of CN were rationally tailored through precursor engineering to effectively magnify interfacial internal electric field and minimize diffusion pathway within the VDW heterostructure, realizing optimal charge dynamics in ZIS/DCN. As a result, intensified H2 generation was achieved, which was 350 times higher than pure DCN and outperformed ZIS at the same unit mass. This work offers design principles for VDW heterostructured photocatalysts and accelerates the transition towards a more sustainable manner in biomass reforming.

Realization of Robust and Ambient-Stable Room-Temperature Ferromagnetism in Wide Bandgap Semiconductor 2D Carbon Nitride Sheets.

Due to their weak intrinsic spin-orbit coupling and a distinct bandgap of 3.06 eV, 2D carbon nitride (CN) flakes are promising materials for next-generation spintronic devices. However, achieving strong room-temperature (RT) and ambient-stable ferromagnetism (FM) remains a huge challenge. Here, we demonstrate that the strong RT FM with a high Curie temperature (TC) up to ∼400 K and saturation magnetization (Ms) of 2.91 emu/g can be achieved. Besides, the RT FM exhibits excellent air stability, with Ms remaining stable for over 6 months. Through the magneto-optic Kerr effect, Hall device, X-ray magnetic circular dichroism, and magnetic force microscopy measurements, we acquired clear evidence of magnetic behavior and magnetic domain evolutions at room temperature. Electrical and optical measurements confirm that the Co-doped CN retains its semiconductor properties. Detailed structural characterizations confirm that the single-atom Co coordination and nitrogen defects as well as C-C covalent bonds are simultaneously introduced into CN. Density functional theory calculations reveal that introducing C-C bonds causes carrier spin polarization, and spin-polarized carrier-mediated magnetic exchange between adjacent Co atoms leads to long-range magnetic ordering in CN. We believe that our findings provide a strong experimental foundation for the enormous potential of 2D wide bandgap semiconductor spintronic devices.

Ultrasonic neural regulation over two-dimensional graphene analog biomaterials: Enhanced PC12 cell differentiation under diverse ultrasond excitation

Two-dimensional (2D) biomaterials, with unique planar topology and quantum effect, have been widely recognized as a versatile nanoplatform for bioimaging, drug delivery and tissue engineering. However, during the complex application of nerve repair, in which inflammatory microenvironment control is imperative, the gentle manipulation and trigger of 2D biomaterials with inclusion and diversity is still challenging. Herein, inspired by the emerging clinical progress of ultrasound neuromodulation, we systematically studied ultrasound-excited 2D graphene analogues (graphene, graphene oxide, reduced graphene oxide (rGO) and carbon nitride) to explore their feasibility, accessibility, and adjustability for ultrasound-induced nerve repair in vitro. Quantitative observation of cell differentiation morphology demonstrates that PC12 cells added with rGO show the best compatibility and differentiation performance under the general ultrasound mode (0.5 w/cm2, 2 min/day) compared with graphene, graphene oxide and carbon nitride. Furthermore, the general condition can be improved by using a higher intensity of 0.7 w/cm2, but it cannot go up further. Later, ultrasonic frequency and duty cycle conditions were investigated to demonstrate the unique and remarkable inclusion and diversity of ultrasound over conventional electrical and surgical means. The pulse waveform with power of 1 MHz and duty cycle of 50 % may be even better, while the 3 MHz and 100 % duty cycle may not work. Overall, various graphene analog materials can be regarded as biosafe and accessible in both fundamental research and clinical ultrasound therapy, even for radiologists without material backgrounds. The enormous potential of diverse and personalized 2D biomaterials-based therapies can be expected to provide a new mode of ultrasound neuromodulation.

The potential of 2D carbon nitride monolayer as an efficient adsorbent for capturing mercury: A DFT study

Owing to its large surface area and the close similarity between nitrogen and mercury (Hg) in C3N, two-dimensional C3N monolayer has the potential of controlling the release of gaseous Hg0. Using density functional theory (DFT), we investigated the adsorption and conversion mechanism of Hg species on this monolayer surface. The findings demonstrated that C4N2 site on the surface of the C3N monolayer is more capable of adsorbing Hg0 than C6 site. Also, the recovery time of the C3N monolayer for Hg0 was approximately 17.63 s and 3.49 μs at 298 and 400 K, respectively. The analyses of electronic structure, charge transport, geometric structure, and adsorption stability demonstrated that the C3N monolayer is an encouraging material for Hg0 adsorption. The C3N monolayer could adsorb the oxidizing species of mercury (namely HgBr, HgCl, HgS, and HgO,) more easily than Hg0, with higher adsorption energy. Overall, the C3N monolayer is a promising sorbent material, which is capable of controlling gaseous mercury in an efficient way.

Novel and facile strategy for immobilization of Ag3PW12 crystals on graphitic carbon nitride (g-C3-N4) sheets, a superior photocatalyst for decomposition of organic waste

The high electron-holes recombination rate in pure graphitic carbon nitride (C3–N4) restrict their photocatalytic efficiency. In this research work, we successfully immobilized Ag3PW12O40 a polyoxometalate-base crystal on graphitic carbon nitride 2D sheet through physical grinding method to prevent charges recombination on the surface. Both the materials were prepared separately and then grinded after mixing, to get C3–N4@Ag3PW12 heterojunction. The prepared C3–N4@Ag3PW12 composites were tested with different characterization techniques to confirm its structural integrity and successful fabrication of heterojunction. The composite catalyst showed expansion in UV light absorbance where it promotes from 406 nm to 454 nm for pure C3–N4 and composite C3–N4@Ag3PW12-30 % respectively. The composite showed better electron-holes separation, confirmed from its electrochemical performance such as TPC (total photocurrent) and PL data. The prepared catalysts were tested for the degradation of two types of organic dyes such as methylene blue and Rhodamine B under photoirradiation. The C3–N4@Ag3PW12-30 % composite photocatalyst showed efficient photocatalytic activity and removed 99 % methylene blue in 75 min while removed 99.4 % Rhodamine B in 60 min while the pure Ag3PW12 and C3–N4 could only remove 26.3 % and 37.7 % methylen blue and 43.54 % and 53.38 % rhodamin B respectively, in the same conditions. The results show that, the Ag3PW12 crystals deposition on C3–N4 2D sheets is a preferred approach to enhance the catalytic performance of C3–N4 2D sheet.

Carbon nitride (C3N3) decorated with non-noble metal Ni2P Co-catalyst based nanocomposites for photocatalytic water splitting

Carbon nitrides based 2D materials have been recently explored as visible light harvesting photocatalysts due to their unique optoelectronic properties. However, these materials require strategies to improve their photoconversion efficiencies by improving the separation of photoexcited charge carriers and minimizing their recombination. Here in this paper, we report the synthesis of 2D carbon nitride with formula C3N3 decorated with non-noble metal nickel phosphide (Ni2P) co-catalyst-based nanocomposites (Ni2P/C3N3) for the enhanced photoelectrochemical water splitting. The ratio of Ni2P co-catalyst was varied from 1%, 2% and 3% in the nanocomposites. Under similar set of experimental conditions, the 2% Ni2P co-catalyst loaded photocatalyst (2% Ni2P/C3N3) showed significant enhancement in the photocurrent (43 µA/cm2) in comparison to the pristine C3N3 (23 µA/cm2) under 1 sun light irradiation. In addition, the 2% Ni2P/C3N3 photocatalyst exhibited enhanced H2 production rate (148 μmol h−1 g−1) than pure C3N3 (60 μmol h−1 g−1). In addition, the 2% Ni2P/C3N3 nanocomposites demonstrated higher photostability. The H2 production rate was almost the same after eight cycles conducted within 65 h of time. Moreover, Ni2P/C3N3 nanocomposites are low cost, naturally abundant and environmentally friendly.