Oxide-derived Cu (OD−Cu) featured with surface located sub-20 nm nanoparticles (NPs) created via surface structure reconstruction was developed for electrochemical CO 2 reduction (ECO 2 RR). With surface adsorbed hydr...
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Oxide-derived Cu (OD−Cu) featured with surface located sub-20 nm nanoparticles (NPs) created via surface structure reconstruction was developed for electrochemical CO 2 reduction (ECO 2 RR). With surface adsorbed hydroxyls (OH ad ) identified during ECO 2 RR, it is realized that OH ad , sterically confined and adsorbed at OD−Cu by surface located sub-20 nm NPs, should be determinative to the multi-carbon (C 2 ) product selectivity. In situ spectral investigations and theoretical calculations reveal that OH ad favors the adsorption of low-frequency *CO with weak C≡O bonds and strengthens the *CO binding at OD−Cu surface, promoting *CO dimerization and then selective C 2 production. However, excessive OH ad would inhibit selective C 2 production by occupying active sites and facilitating competitive H 2 evolution. In a flow cell, stable C 2 production with high selectivity of ∼60 % at −200 mA cm −2 could be achieved over OD−Cu, with adsorption of OH ad well steered in the fast flowing electrolyte.
Microalgae have great potential in producing energy-dense and valuable products via thermochemical processes. Therefore, producing alternative bio-oil to fossil fuel from microalgae has rapidly gained popularity due t...
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Herein, we have demonstrated the control over the structure of precatalysts to tune the properties of the active catalysts and their water oxidation activity. The reaction of K 3 [Fe(CN) 6 ] and Na 2 [Fe(CN) 5 (NO)] w...
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Herein, we have demonstrated the control over the structure of precatalysts to tune the properties of the active catalysts and their water oxidation activity. The reaction of K 3 [Fe(CN) 6 ] and Na 2 [Fe(CN) 5 (NO)] with Co(OH) 2 @CC produced precatalysts PC-1 and PC-2, respectively, with distinct structural and electronic features. The replacement of the −CN group with strong π-acceptor −NO modulates the electronic and atomic structure of PC-2. As a result, a facile electrochemical transformation of PC-2 into active catalyst Fe−Co(OH) 2 -Co(O)OH (AC-2) has been attained only in 15 CV cycles while 600 CV cycles are required for the electrochemical activation of PC-1 into AC-1. The X-ray absorption studies reveal the contraction of the Co−O and Fe−O bond in AC-2 because of the presence of a higher amount of Co 3+ and Fe 3+ than in AC-1. The high valent Co 3+ and Fe 3+ modulates the electronic properties of AC-2 and assists in the O−O bond formation, leading to the improved water oxidation activity.
The recombination of photogenerated charge carriers severely limits the performance of photoelectrochemical (PEC) H 2 production. Here, we demonstrate that this limitation can be overcome by optimizing the charge tran...
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The recombination of photogenerated charge carriers severely limits the performance of photoelectrochemical (PEC) H 2 production. Here, we demonstrate that this limitation can be overcome by optimizing the charge transfer dynamics at the solid–liquid interface via molecular catalyst design. Specifically, the surface of a p-Si photocathode is modulated using molecular catalysts with different metal atoms and organic ligands to improve H 2 production performance. Co(pda-SO 3 H) 2 is identified as an efficient and durable catalyst for H 2 production through the rational design of metal centers and first/second coordination spheres. The modulation with Co(pda-SO 3 H) 2 , which contains an electron-withdrawing −SO 3 H group in the second coordination sphere, elevates the flat-band potential of the polished p-Si photocathode and nanoporous p-Si photocathode by 81 mV and 124 mV, respectively, leading to the maximized energy band bending and the minimized interfacial carrier transport resistance. Consequently, both the two photocathodes achieve the Faradaic efficiency of more than 95 % for H 2 production, which is well maintained during 18 h and 21 h reaction, respectively. This work highlights that the band-edge engineering by molecular catalysts could be an important design consideration for semiconductor–catalyst hybrids toward PEC H 2 production.
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