Non-bonding modulations between single atomic cerium and monodispersed selenium sites towards efficient oxygen reduction

Currently,dual atomic catalysts(DACs)with neighboring active sites for oxygen reduction reaction(ORR)still meet lots of challenges in the synthesis,especially the construction of atomic pairs of elements from different blocks of the periodic table.Herein,a“rare earth(Ce)-metalloid(Se)”non-bonding heteronuclear diatomic electrocatalyst has been constructed for ORR by rational coordination and carbon support defect engineering.Encouraging,the optimized Ce-Se diatomic catalysts(Ce-Se DAs/NC)displayed a half-wave potential of 0.886 V vs.reversible hydrogen electrode(RHE)and excellent stability,which surpass those of separate Ce or Se single atoms and most single/dual atomic catalysts ever reported.In addition,a primary zinc-air battery constructed using Ce-Se DAs/NC delivers a higher peak power density(209.2 mW·cm^(−2))and specific capacity(786.4 mAh·gZn^(−1))than state-of-the-art noble metal catalysts Pt/C.Theoretical calculations reveal that the Ce-Se DAs/NC has improved the electroactivity of the Ce-N_(4)region due to the electron transfer towards the nearby Se specific activity(SA)sites.Meanwhile,the more electron-rich Se sites promote the adsorptions of key intermediates,which results in the optimal performances of ORR on Ce-Se DAs/NC.This work provides new perspectives on electronic structure modulations via non-bonded long-range coordination micro-environment engineering in DACs for efficient electrocatalysis.

Synergistic coupling of Ni_(3)ZnC_(0.7)decorated with homogeneous multimetal CoNiCuFe nitrogen-codoped carbon matrix as high-entropy catalysts for efficient overall water splitting

Due to unique electrical properties and high catalytic efficiency,transition metal nitrogen-codoped car-bide(TM-N-C)has attracted tremendous interest as a multifunctional electrocatalyst for water splitting.Unlike traditional single-source modification,herein a novel pomegranate-like high-entropy(HE)elec-trocatalyst of Ni_(3)ZnC_(0.7)decorated with homogeneous multimetal(Fe,Co,Cu,and Ni)nitrogen-codoped carbon matrix(Ni_(3)ZnC_(0.7)@CoNiCuFe-NC)is reported.It can be implemented by the simple thermal an-nealing method of multimetal codoped zeolitic imidazolate framework(ZIF).Benefiting from the syn-ergistic effects of plentiful TM-N-C species,template effect of ZIF and distinct nanoporous structure,HE electrocatalyst Ni_(3)ZnC_(0.7)@CoNiCuFe-NC exhibits outstanding electrocatalytic performance.When ap-plied in strong alkaline electrolyte(1.0 M KOH),the overpotentials of Ni_(3)ZnC_(0.7)@CoNiCuFe-NC present as low as 202 and 97 mV for oxygen evolution reaction(OER)and hydrogen evolution reaction(HER)at 10 mA cm^(−2)current density.Surprisingly as a bifunctional electrode,it can achieve the low cell voltage of 1.53 V at 10 mA cm^(−2)current density for overall water splitting,which is comparable to conventional IrO_(2)||Pt/C electrode and superior to the recently reported analogous bifunctional catalysts.Thus,the work proposes the direction for the rational design of homogeneous distribution of TM-N-C material for water splitting in the green hydrogen energy industry.