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J Po lue ran sael od fo Mn aot te rai ad l js u Cs ht emm ai rs gt ri yn sA
Journal Name
is almost 7 times higher than that on SnO
ARTICLE
-2
2
/AC (4 mA cm ). The
DOI: 10.1039/C9TA05937G
2 2 2
FEformate value for SnO /PC as well as the partial current density construct 3D porous SnO /PC with high SnO loading has been
rank as top-tier in Sn-based catalysts (Fig. 3c and Table S2 in developed. Taking the advantage of abundant macropores
2
ESI†). The stability of SnO /PC was further demonstrated by
providing mass and charge transport highways and micropores
inhibiting the protons transfer to active sites and thus
suppressing the HER process, SnO
activity and formate selectivity for the CO
2
/PC exhibits a superior
RR in aqueous
2
medium with a high faradaic efficiency of 92% and partial
current density of 29 mA cm- at -0.86 V, which significantly
2
2
outperform the SnO /AC counterpart with micropore-
dominated structure. These results shed light on the design of
efficient electrocatalysts via engineering pore structures for
other heterogeneous electrochemical reactions.
Fig. 4 (a) The FEformate and (b) current densities as a function of the rotation speed of
SnO /PC and SnO /AC for CO RR.
Conflicts of interest
2
2
2
There are no conflicts to declare.
continuous CO
d). The current density was stable at over 30 mA cm and the
FEformate was retained > 80% during the entire period, suggesting Acknowledgments
2
electroreduction at -0.86 V for over 10 h (Fig.
-2
3
the excellent long-term durability of SnO
FEformate from 92% to 80% after the 10 h electrolysis is likely
caused by the agglomerated SnO nanoparticles (Fig. S10, ESI†).
The large difference of CO RR activity between SnO /PC and
SnO /AC could be ascribed to the advantages of interconnected
D carbon nanosheets with abundant micropores and
macropores in PC support over mesopores-dominated AC
support. The CO is electrochemically reduced with the
2
/PC. The decrease of
The authors acknowledge the financial support from the
National Key Research and Development Program of China
2
(2016YFB0101202), National Natural Science Foundation of
2
2
China (91645123 and 21773263), Strategic Priority Research
Program of the Chinese Academy of Sciences (Grant No.
XDB12020100), and the National Postdoctoral Program for
Innovative Talents (BX201700250).
2
2
2
depletion of local protons and production of hydroxide ions,
leading to the increased local pH value near the active sites and
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thus effectively suppressing the HER process.
nanospace would be confined in the micropores in PC, favouring
the CO RR process. While the macropores in PC could provide
D networks for efficient mass and electron transportation,
making the active sites confined in the above nanospace being
Such a
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3
2.
2
reduction
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2
(
1
6
equilibrate the local proton concentration, leading to the
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varied from 200 to 800 rpm at -0.86 V (Fig. S11, ESI†). As shown
in Fig. 4, the FEformate and total current densities over SnO /PC
remain nearly unchanged, suggesting mass transportation is not
a determining factor on SnO /PC for CO RR due to the presence
of abundant macropores. On the contrary, the total current
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2
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rotation rates, indicating that more active sites are accessible
due to the facilitated mass transportation. While the FEformate of
9
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SnO
2
/AC keeps nearly constant, which is caused by the
/AC for CO RR.
unaltered intrinsic activity in SnO
2
2
4
. Conclusions
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