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Interlayer Palladium-Single-Atom-Coordinated Cyano-Group-Rich Graphitic Carbon Nitride for Enhanced Photocatalytic Hydrogen Production Performance
ACS Catalysis ( IF 11.3 ) Pub Date : 2022-04-14 , DOI: 10.1021/acscatal.2c00427
Miao Ren 1 , Xueyan Zhang 1 , Yunqing Liu 1 , Guang Yang 1 , Lang Qin 1 , Jiaqi Meng 1 , Yihang Guo 1 , Yuxin Yang 1
Affiliation  

To improve the photocatalytic hydrogen evolution activity of palladium-assisted graphitic carbon nitride (g-C3N4), here, palladium-single-atom-coordinated cyano-group-rich g-C3N4 (Pd/DN-UCN) are synthesized, and the synthesis process includes copolymerization of urea-derived supramolecular aggregates and NH4Cl followed by wet impregnation. By combining powerful characteristic results and theoretical calculations, the formation mechanism of Pd single atoms on the ultrathin, mesoporous cyano-group-rich g-C3N4 nanosheets is proposed, highlighting that the Pd single atoms are firmly stabilized in the interlayers of g-C3N4 nanosheets caused by the combination of the physical confinement effect of ultrathin, mesoporous g-C3N4 nanosheets and coordination bonding of cyano groups with Pd atoms; additionally, Pd–N3 coordination in the Pd/DN-UCN heterojunctions is confirmed, in which one Pd atom coordinates with one N atom of the cyano group and two sp2-hybridized N atoms in the adjacent layer. The presence of cyano groups and Pd–N coordination in the Pd/DN-UCN induces a midgap state in the band structure of g-C3N4. At optimal Pd loading levels (0.16%), the synthesized 0.16%Pd/DN-UCN0.50 exhibits enhanced photocatalytic hydrogen production activity as compared to electrostatically stabilized Pd single atoms on the “sixfold cavities” of g-C3N4, and apparent quantum yield values at the stationary point of the 0.16%Pd/DN-UCN0.50 concentration (1.2 g L–1) can reach up to 14.6, 15.8, 4.69, and 3.05% under monochromatic light irradiation at 365, 400, 450, and 550 nm, respectively. The cooperation of significantly boosted transfer of photoexcited electrons to atomically dispersed Pd sites via as-built interlayer Pd–N coordination delivery channels and the maximal Pd atom utilization efficiency dominates the enhanced photocatalytic hydrogen evolution activity of Pd/DN-UCN.

中文翻译:

用于增强光催化制氢性能的层间钯-单原子配位氰基富石墨氮化碳

为了提高钯辅助石墨氮化碳 (gC 3 N 4 )的光催化析氢活性,本文合成了钯单原子配位富氰基 gC 3 N 4 (Pd/ DN -UCN ),其合成过程包括尿素超分子聚集体与NH 4 Cl共聚后湿法浸渍。通过结合强有力的特征结果和理论计算,提出了Pd单原子在超薄介孔富氰基gC 3 N 4纳米片上的形成机制,强调了Pd单原子牢固地稳定在gC 3的夹层中N 4纳米片是由超薄介孔gC 3 N 4纳米片的物理限制效应和氰基与Pd原子的配位键结合产生的;此外,证实了 Pd/DN -UCN 异质结中的 Pd-N 3 配位其中一个 Pd 原子与氰基的一个 N 原子和相邻层中的两个 sp 2杂化 N 原子配位。Pd/D N -UCN中氰基和 Pd-N 配位的存在在 gC 3 N 4的能带结构中诱导了中间带隙状态。在最佳 Pd 负载水平 (0.16%) 下,合成的 0.16% Pd/ DN -UCN 0.50与 gC 3 N 4的“六倍腔”上的静电稳定 Pd 单原子相比,表现出增强的光催化制氢活性,以及​​在 0.16% Pd/D N -UCN 0.50浓度(1.2 g L –1 ) 在 365、400、450 和 550 nm 的单色光照射下可分别达到 14.6、15.8、4.69 和 3.05%。通过构建的层间 Pd-N 配位传递通道显着促进光激发电子向原子分散的 Pd 位点的转移和最大 Pd 原子利用效率的协同作用主导了 Pd/DN -UCN 增强的光催化析氢活性
更新日期:2022-04-14
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