Nitrogen‐Doped Graphene for Photocatalytic Hydrogen Generation

Abstract

Photocatalytic hydrogen (H2 ) generation in a water splitting process has recently attracted tremendous interest because it allows the direct conversion of clean and unlimited solar energy into the ideal energy resource of H2 . For efficient photocatalytic H2 generation, the role of the photocatalyst is critical. With increasing demand for more efficient, sustainable, and cost-effective photocatalysts, various types of semiconductor photocatalysts have been intensively developed. In particular, on the basis of its superior catalytic and tunable electronic properties, nitrogen-doped graphene is a potential candidate for a high-performance photocatalyst. Nitrogen-doped graphene also offers additional advantages originating from its unique two-dimensional sp(2) -hybridized carbon network including a large specific surface area and exceptional charge transport properties. It has been reported that nitrogen-doped graphene can play diverse but positive functions including photo-induced charge acceptor/meditator, light absorber from UV to visible light, n-type semiconductor, and giant molecular photocatalyst. Herein, we summarize the recent progress and general aspects of nitrogen-doped graphene as a photocatalyst for photocatalytic H2 generation. In addition, challenges and future perspectives in this field are also discussed.

Heteroatom‐Doped Carbonaceous Photocatalysts for Solar Fuel Production and Environmental Remediation

“…N‐doped graphene provides many advantages originating from its unique 2D sp 2 ‐hybridized carbon network including a large S BET and unexpected charge transport properties. The N‐doped graphene for photocatalytic applications has been well summarized in previous reviews . Therefore, N‐doped graphene shall not be covered by this Review, although it is of critical importance.…”

“…N‐doped carbon nanostructures are a related type of photocatalyst. For example, N‐doped graphene has been considered as a potential candidate for high‐performance photocatalysts . N‐doped graphene provides many advantages originating from its unique 2D sp 2 ‐hybridized carbon network including a large S BET and unexpected charge transport properties.…”

“…Heterogeneous solid catalysis, especially heterogeneous photocatalysis, serves as ap owerful tool ford ealingw ith the global energy crisis on fossil fuel depletion and the growing environmental pollution problems. [1][2][3][4][5][6][7][8][9][10][11] Heterogeneous catalysisr emains active and attractive at the heart of modern materials chemistry,g reen and sustainable chemistry,t he energy and environmental domains from academic to practical aspects. Inspired by plant photosynthesis, photocatalytic reduction for the production of hydrogen, [12][13][14][15][16][17][18][19][20][21][22] hydrocarbonf uels, as well as methanol,f ormic acid, CO, and other chemicals via CO 2 , [23][24][25][26][27][28][29][30][31] and the respective photocatalytic oxidationf or the degradation of environmental pollutants, [32][33][34][35] remain criticalr esearch areas, besides photocatalytic organic synthesis (Figure 1).…”

“…Many approaches have been attempted to address the above issues, like structural and morphology design, different preparation method and conditions, doping by heteroatoms, loading precious metals like Pt as cocatalyst, the formation of hybrid semiconductorsa nd their combination. [1][2][3][4][5][6][7][8][9][10][11] Through the adjustment of component, morphology,t exture, and the rational design and fabrication of novel carbonaceous heterojunctions and isotype junctions, the light absorption capacity,t he separation and transport efficiency of photoexcited charge carriers,t he resistance of recombination of photogenerated electron-holep airs, redox potential, as well as the properties of surfacea ctive sites and their accessibility could be efficiently improved. The heteroatom doping approach of introducing impurities into a matrix of nanocarbon materials, through surface transfer doping and substitutional doping, presents an avenue to efficiently enhancep hotocatalytic properties of carbonaceousm aterials through the improvedo ptical and electrochemical properties, structurala nd textural characteristics,t he adsorptive and mass transfer behavior,a nd the properties of active sites.…”

“…The heteroatom doping approach of introducing impurities into a matrix of nanocarbon materials, through surface transfer doping and substitutional doping, presents an avenue to efficiently enhancep hotocatalytic properties of carbonaceousm aterials through the improvedo ptical and electrochemical properties, structurala nd textural characteristics,t he adsorptive and mass transfer behavior,a nd the properties of active sites. [1,4,[7][8][9][10][77][78][79][80][81][82][83][84] As ac onsequence, the doping of photocatalysts garnerscontinually growing interest. By searching "photocatalysis" and then refining by "doping" (SciFinder,o nA pril 20, 2017),2 0799 publications can be obtained.I ndicated in Figure2is the explosive growth of doping of photocatalysts in the last ten years.…”