Interfacial Electronic Rearrangement and Synergistic Catalysis for Alkaline Water Splitting in Carbon-Encapsulated Ni (111)/Ni3C (113) Heterostructures
Round 1
Reviewer 1 Report
This study employs synthesize Ni–Ni3C/NC heterojunction electrocatalyst, demonstrating superior HER activities and good stabilities with a small overpotential of –29 mV at 10 mA/cm2, a low Tafel slope of 59.96 mV/dec in alkaline surroundings. The heterostructure electrocatalyst operates at 1.55 V and 1.26 V to reach 10 and 1 mA cm–2 in two–electrode measurements for overall alkaline water splitting. All the experiments are presented thoroughly, which deserves publication in this journal. Therefore, I recommend its acceptance after addressing the following major comments.
1. The resolution of the images in Fig. 1 is not clear. So, please reorganize with a proper resolution. Furthermore, authors are suggested to rename Fig. (i-J) as i, i1, i2, i3, and j, respectively. In addition, the size of the scale bar is written in the Fig. caption. So, please present together with the scale bar in the Figure.
2. The authors only listed the surface area and pore size distribution but no detailed analysis. In addition, the morphological superiority of Ni–Ni3C/NC should be compared. What is the effect of morphology on the Ni–Ni3C/NC catalyst?
3. The authors should include supporting files.
4. On page 2 of 15, lines 184, 185, and 225, there are some typo errors like Ni 2P3/2, Ni0 2p3/2, j0.
5. What is the role of nitrogen in Ni–Ni3C/NC? Which nitrogen is responsible for electrochemical performance?
6. In Fig. 4 (f) and (i), the long–term stability measurement of Ni–Ni3C/NC–500 at a current density of 25 mA cm-2 for 25 h displayed certain variations in the potentials. Please, mention the percentage of the retention/degradation potentials from the initial to the final time period of the stability test.
7. To confirm the successful synthesis of Ni–Ni3C/NC, the authors suggest presenting additional experiments such as micromorphology, composition, and electronic states of elements. It might be better if the authors provide an insight discussion, such as Carbon, 179, July 2021, Pages 89-99; Composites Part B: Engineering, Volume 239, 15 June 2022, 109992; Materials Today Nano, 17, March 2022, 100146.
Author Response
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Author Response File: 
Author Response.pdf
Reviewer 2 Report
The present manuscript "Interfacial Electronic Rearrangement and Synergistic Catalysis 2 for Alkaline Water Splitting in Carbon Encapsulated Ni 3 (111)/Ni3C (113) Heterostructure" is interesting and I suggest its acceptance after major changes
1. Could the author explain HER in full form when used the first time in the abstract which you have used in the introduction?
2. Please use the same reference style in the manuscript. Some references are written after the comma, some before a comma, and some after a full stop.
3. Please check line 43 is incomplete.
4. Figure 1 is not clear. Please improve the resolution.
5. The authors should perform TGA for thermal stability. There is a need for recent references related to this study. Unfortunately, the authors used no reference for the years 2022 and 2021.
6. English corrections are required.
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
In current work (catalysts-1988520), the authors designed and fabricated carbon encapsulated Ni(111)/Ni3C(113) heterostructure electrocatalyst, that revealed superior HER performance and excellent stability with a small overpotential of –29 mV at 10 mA/cm2, and a low Tafel slope of 59.96 mV/dec in alkaline electrolyte, which is almost closed to that of the commercial Pt/C catalyst and higher than those of the reported Ni–based catalysts. The heterostructure electrocatalyst operates at 1.55 V and 1.26 V to reach 10 and 1 mA cm–2 in two–electrode measurements for overall alkaline water splitting, corresponding to the 79% and 98% electricity–to–fuel conversion efficiency with respect to the lower heating value of hydrogen. In fact, this is an excellent work in the field. The authors well organized the whole manuscript. The quality of the figures is excellent. The designed scheme is very clear. I strongly recommend its publication in Catalysts. Some minor comments should be addressed.
1. It has been demonstrated that there exist abundant coordinated unsaturated sites on the surface of Ni-based catalysts which consequently improves the catalytic activity. The authors should address those sites in the introduction part. Authors should refer to the following reference. https://doi.org/10.1016/j.apcatb.2022.121088
2. Some minor typo-errors and grammatical mistakes exist throughout the manuscript. Authors should carefully revise the whole manuscript and do corrections.
3. Page numbers should be assigned to some of the references.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
All the suggested corrections are done carefully, and this article can be accepted for publication now.
