One-pot molten salt method for constructing CdS/C3N4 nanojunctions with highly enhanced photocatalytic performance for hydrogen evolution reaction.
One-pot molten salt method for constructing CdS/C3N4 nanojunctions with highly enhanced photocatalytic performance for hydrogen evolution reaction.
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DOI：
10.1016/j.jes.2021.05.019
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发表时间：
2022-02
影响因子：
6.9
通讯作者：
Weijia Zhao;Hongyun Niu;Yongliang Yang;Hongzhou Lv;Jungang Lv;Yaqi Cai
中科院分区：
文献类型：
--
作者：
Weijia Zhao;Hongyun Niu;Yongliang Yang;Hongzhou Lv;Jungang Lv;Yaqi Cai
构建异质结光催化剂以有效利用太阳能，是解决能源危机和减少环境污染的重要途径。在本研究中，我们利用一个容易发生的放热化学反应释放的能量作为驱动力来触发CdS和C3 N4纳米复合材料的形成，成功地制备了CdS和C3 N4纳米复合材料与硝酸镉和硫脲在没有添加任何溶剂和惰性气体的保护下，在初始温度，略高于硫脲的熔点。在可见光（λ > 420 nm）照射下，CdS/C3 N4材料的光催化析氢速率高达15,866 μmol/（g·hr），分别是C3 N4和CdS的89倍和9倍。CdS/C3 N4 -1：2-200-2（CdS/C3 N4 - 1：2 - 200-2表示Cd与S的比例为1：2，反应温度设定为200°C，反应2小时）在λ = 420 ± 15 nm处的表观量子效率（AQE）达到3.25%。CdS/C_3N_4的HER效率在辐照24小时后没有衰减。密度泛函理论计算表明，C3 N4与CdS之间的电荷差导致了C3 N4与CdS之间的内电场，从而更有效地促进了CdS与C3 N4之间的光生电子转移.因此，大多数HER应该发生在光生电子聚集的C3 N4表面，这在很大程度上保护了CdS免受光腐蚀。
The construction of heterojunction photocatalysts for efficiently utilizing solar energy has attracted considerable attention to solve the energy crisis and reduce environmental pollution. In this study, we use the energy released from an easily-occurred exothermic chemical reaction to serve as the drive force to trigger the formation of CdS and C3N4nanocomposites which are successfully fabricated with cadmium nitrate and thiourea without addition of any solvents and protection of inert gas at initial temperature, a little higher than the melting point of thiourea. The as-prepared CdS/C3N4materials exhibit high efficiency for photocatalytic hydrogen evolution reaction (HER) with the HER rate as high as 15,866 μmol/(g∙hr) under visible light irradiation (λ > 420 nm), which is 89 and 9 times those of pristine C3N4and CdS, respectively. Also, the apparent quantum efficiency (AQE) of CdS/C3N4–1:2–200–2 (CdS/C3N4–1:2–200–2 means the ratio of Cd to S is 1:2 and the reaction temperature is set at 200°C for two hours) reaches 3.25% at λ = 420 ± 15 nm. After irradiated for more than 24 hr, the HER efficiencies of CdS/C3N4do not exhibit any attenuation. The DFT calculation suggests that the charge difference causes an internal electric field from C3N4pointing to CdS, which can more effectively promote the transfer of photogenerated electrons from CdS to C3N4. Therefore, most HER should occur on C3N4surface where photogenerated electrons accumulate, which largely protects CdS from photo-corrosion.