Sea-urchin-structure g-C3N4 with narrow bandgap (˜2.0 eV) for efficient overall water splitting under visible light irradiation
Sea-urchin-structure g-C3N4 with narrow bandgap (˜2.0 eV) for efficient overall water splitting under visible light irradiation
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DOI：
10.1016/j.apcatb.2019.03.010
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发表时间：
2019-07
期刊：
影响因子：
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通讯作者：
Yunxiong Zeng;Hao Li;Jinming Luo;Jili Yuan;Longlu Wang;Chengbin Liu;Yingchun Xia;Meijun Liu
中科院分区：
文献类型：
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作者：
Yunxiong Zeng;Hao Li;Jinming Luo;Jili Yuan;Longlu Wang;Chengbin Liu;Yingchun Xia;Meijun Liu
宽的带隙和光激发的h+-e -对的有害复合是使用g- c3n4可见光水分裂的致命缺陷。本文采用热液策略制备了具有~ 2.0 eV带隙的海胆结构g-C3N4（CNSC）。值得注意的是，CNSC可以有效地抑制+-e−对复合，并且具有窄的带隙，可以利用更多的可见光。与NHE相比，常规g- c3n4的带隙为~ 2.7 eV，价带电位为+1.83 V，而CNSC的价带电位为+1.55 V。因此，CNSC不会产生H2O2，而H2O2会钝化g-C3N4。密度泛函理论（DFT）证实，CNSC中的Ctriple键dn、Cdouble键do和单键doh基团使Pt的d波段中心更接近费米能级，从而使吸附质的稳定性更好，催化性能更高。在可见光（λ≥420 nm）下，3 wt% Pt/CNSC光沉积Pt可产生41.5 μmol g-1h-1和20.3 μmol g-1h-1的h2o2析出率（HER和OER）（在420±10 nm时表观量子效率为0.43%），是2 wt% Pt/体g- c3n4光沉积Pt的30倍。本研究提供了一种构建窄带隙分层纳米结构g- c3n4的创新方法，为水裂解光催化剂的发展铺平了道路。
A broad bandgap and detrimental recombination of photoexcitedh+-e−pairs are fatal deficiencies for using the g-C3N4visible light water splitting. Herein, a sea-urchin-structure g-C3N4(CNSC) with ∼2.0 eV bandgap was prepared using a hydrothermal strategy. It is important to note that CNSC can efficiently suppressh+-e−pair recombination and has a narrow bandgap which can utilize more visible light. Conventional g-C3N4has a ∼2.7 eV bandgap and valence band (VB) potential of +1.83 V vs. NHE but the VB of CNSC is +1.55 V. As a result, CNSC does not create H2O2, which can passivate g-C3N4. Density functional theory (DFT) confirms that Ctriple bondN, Cdouble bondO, and single bondOH groups in the CNSC shift the d-band centre of Pt closer to Fermi level, leading to better stabilization of adsorbate and higher catalytic performance. Photo-depositing Pt on the CNSC, 3 wt% Pt/CNSC produces H2and O2evolution rate (HER and OER) of 41.5 and 20.3 μmol g-1h-1(apparent quantum efficiency: 0.43% at 420 ± 10 nm), respectively, 30 times greater than HER of 2 wt% Pt/bulk g-C3N4in overall water splitting under visible-light (λ ≥ 420 nm). This work provides an innovative approach to construct hierarchical nanostructure g-C3N4with narrow bandgap and paves the pathway for development of water splitting photocatalysts.