Synergies of Adjacent Sites in Atomically Dispersed Ruthenium toward Achieving Stable Hydrogen Evolution

Abstract

It is a challenge to fabricate atomically dispersed metal clusters in polymeric carbon nitride (PCN) for durable photocatalytic reactions owing to the thermodynamic stability limitation. Herein, atomically dispersed Ru clusters are implanted into the PCN skeleton matrix based on an ionic diffusion and coordination (IDC) strategy, the stability of which is improved owing to the robust Ru−N bonds in the formed RuN 4 and RuN 3 configurations. Additionally, RuN 4 and RuN 3 as charge transport bridges between two adjacent melon strands efficaciously conquer hydrogen bond restriction in the skeleton to facilitate the in-plane mobility and separation of charge carriers. Moreover, the synergistic effect of adjacent Ru atoms is triggered on the assembled RuN 3 −RuN 4 and RuN 3 −RuN 3 in the atomically dispersed Ru clusters to significantly decrease hydrogen adsorption energy. As a result, the optimal PCN-Ru photocatalyst achieves nearly 6 times higher than the photocatalytic hydrogen evolution (PHE) rate of the Pt/PCN benchmark and maintains the long-term stable running for 104 h of 26 cycles; its overall PHE performance is far superior to the most of single atoms supported on g-C 3 N 4 photocatalysts reported. The findings here gain new insight into the preparation strategy, structure configuration, and reaction mechanism for atomically dispersed metal clusters supported on PCN, which further stimulates the intensive investigations toward developing more efficient and stable PCN-like photocatalytic materials.

Tailoring a sulfur doped carbon nitride skeleton to enhance the photocatalytic hydrogen evolution activity

“…41 All x -DZCN samples revealed an evident redshift and broadened visible light absorption range from 470 nm to over 600 nm in contrast to CN, signifying the enhanced solar utilization. 29 Among the samples, the 20-DZCN presented the most obvious trend mentioned above, suggesting the most effective utilization of visible light. The band gap ( E g ) of 20-DZCN and CN was calculated using the Tauc formula αhν = A ( hν − E g ) n /2 .…”

“…2e) present the same binding signals, where the weaker signal at 288.2 eV (NQC-N/C-NQC) and strong signal at 284.8 eV (CQC/C-C) stem from the sp 2 -hybridized carbon and graphitic carbon, respectively. 12,29 The divided O 1s spectra of CN and 20-DZCN (Fig. 2f) also revealed the same binding signals, where the peaks at 533.2 and 531.9 eV are believed to be from the adsorbed H 2 O.…”

“…4c were used to investigate the flat band ( E f ), which were −0.56 (20-DZCN) and −0.02 eV (CN) vs. Ag/AgCl, converted to −0.36 and 0.18 eV vs. NHE. Since the E CB values of the majority of n-type semiconductors (positive slope) are 0.1 eV below their E f ; 11,29 the E CB of 20-DZCN and CN are −0.46 and 0.08 eV vs. NHE, respectively. Accordingly, the E VB of 20-DZCN and CN are 2.33 and 2.97 eV, respectively, based on E VB = E g + E CB .…”

Adjusting Surface Oxidized Layer of CoTe on PCN via In Situ N-Doping Strategy to Promote Charge Separation of Z-Scheme Heterojunction for Propelling Photocatalytic CO2 Reduction

“…In addition, the band gap of samples is calculated using the Tauc formula. 42 On the base of the plots of (αhν) 1/2 vs hν in Figure 5b, the PCN band gap is reduced from the initial 2.67 to 2.37 eV after incorporating CoTe on the surface. The extended light harvest range and reduced band gap mean that the 1D/2D CoTe/PCN heterojunction has higher solar utilization and is more easily excited than PCN, facilitating the photocatalytic CO 2 R reaction.…”

“…Due to the coupling effect of CoTe, the absorption edge of CoTe/PCN-10 undergoes an evident red shift, as well as the light harvest range broadens to the entire visible and near-infrared regions. In addition, the band gap of samples is calculated using the Tauc formula . On the base of the plots of (α h ν) 1/2 vs h ν in Figure b, the PCN band gap is reduced from the initial 2.67 to 2.37 eV after incorporating CoTe on the surface.…”