Electron acceptor of Ni decorated porous carbon nitride applied in photocatalytic hydrogen production

Abstract

Nickel, a non-noble metal, is one of the most promising candidates for photocatalysis because it is inexpensive and an earth-abundant metal. Herein, Ni/CM-CN nanocomposites with Ni as a cocatalyst were synthesized by a simple solvothermal method. Field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed that Ni nanoparticles were loaded onto the surface of CM-CN. The prepared Ni/CM-CN nanocomposites exhibited an enhanced hydrogen evolution activity. The most active catalyst contained 10% Ni and produced H at a rate of 313.2 μmol h g, which was obviously higher than that of pure CM-CN. The results of photoluminescence (PL) and photoacoustics (PA) studies indicated that the recombination efficiency of photo-induced electron-hole pairs was decreased for CM-Ni10 as compared to that for unmodified CM-CN. The transient photovoltage (TPV) measurements directly demonstrated that the recombination time of electron-hole pairs in CM-Ni10 was prolonged. More importantly, the reversed surface photovoltage (SPV) and the declined surface photocurrent (SPC) response of CM-Ni10 revealed that the photogenerated electrons could be trapped by Ni, leading to a better separation efficiency and a superior hydrogen production. Finally, the possible mechanism is proposed to illuminate the photogenerated charge behavior between CM-CN and Ni, which might provide a theoretical basis to develop efficient cocatalysts for photocatalytic water splitting.

Enhanced Photocatalytic Hydrogen Evolution of NiCoP/g‐C3N4 with Improved Separation Efficiency and Charge Transfer Efficiency

“…The full XPS survey spectrum shows the presence of C, N, Ni, Co, P, and O (O may arise from air contact). High‐resolution XPS spectra of C 1s and N 1s were also obtained to gain more insight into the chemical bonding of g‐C 3 N 4 (Figure b, c) . In particular, the peaks of the C 1s spectrum are centered at around 284.8 and 288.4 eV, are derived from characteristic C−C/C=C and N−C=N/C−NH 2 species in g‐C 3 N 4 .…”

“…High-resolution XPS spectra of C1sa nd N1s were also obtained to gain more insighti nto the chemical bondingo fg -C 3 N 4 (Figure 3b, c). [25,34] In particular, the peaks of the C1ss pectruma re centered at around2 84.8 and 288.4 eV, are derived from characteristic CÀC/C=Ca nd NÀC=N/CÀNH 2 speciesi ng -C 3 N 4 .T he N1ss pectrum of g-C 3 N 4 (Figure 3c) could be divided into four peaks corresponding to sp 2 -hybridized nitrogen (C=NÀC) at 398.9 eV,t ertiaryn itrogen (NC 3 )a t 399.9 eV,a mino functional groups at 401.2 eV,a nd P excitations of the C=Nc onjugateds tructures at 405 eV.…”

g‐C3N4‐Based Heterostructured Photocatalysts

“…Bimetallic cocatalysts such as PtCo, [205] PdAu, [239] PtOAu [240] have exhibited higher H 2 photocatalytic activity than single noble metals. So far, numerous nonnoble metal cocatalysts have proven efficient in enhancing the photo catalytic H 2 generation activity of gC 3 N 4 , including FeO x , [228] MoS 2 , [229,[241][242][243][244] WS 2 , [245] NiS, [246][247][248] Ni 12 P 5 , [249] carbon nanotube (CNT), [232] carbon black, [233] carbon nanofiber, [222] Co(OH) 2 , [250] Ni(OH) 2 , [251,252] Cu(OH) 2 , [253] Ni(dmgH) 2, [254] and Ni [208,255,256] (Table 3). So far, numerous nonnoble metal cocatalysts have proven efficient in enhancing the photo catalytic H 2 generation activity of gC 3 N 4 , including FeO x , [228] MoS 2 , [229,[241][242][243][244] WS 2 , [245] NiS, [246][247][248] Ni 12 P 5 , [249] carbon nanotube (CNT), [232] carbon black, [233] carbon nanofiber, [222] Co(OH) 2 , [250] Ni(OH) 2 , [251,…”

Effect of Alloyed BiOClxBr1‐x Nanosheets Thickness on the Photocatalytic Performance

“…Semiconductor photocatalysis is currently considered as an advanced technology to convert solar energy for photosplitting water, photoreducing CO 2 , and photodegrading toxic pollutants . Among them, the treatment of toxic pollutants is still very concerned.…”