Wang Degao, Wang Ying, Brady Matthew D, Sheridan Matthew V, Sherman Benjamin D, Farnum Byron H, Liu Yanming, Marquard Seth L, Meyer Gerald J, Dares Christopher J, Meyer Thomas J
Department of Chemistry , University of North Carolina Chapel Hill , Chapel Hill , North Carolina 27599 , USA . Email:
Department of Chemistry , Texas Christian University , Fort Worth , Texas 76129 , USA.
Chem Sci. 2019 Mar 14;10(16):4436-4444. doi: 10.1039/c8sc03316a. eCollection 2019 Apr 28.
We describe here the preparation and characterization of a photocathode assembly for CO reduction to CO in 0.1 M LiClO acetonitrile. The assembly was formed on 1.0 μm thick mesoporous films of NiO using a layer-by-layer procedure based on Zr(iv)-phosphonate bridging units. The structure of the Zr(iv) bridged assembly, abbreviated as NiO|-DA-RuCP -Re(i), where DA is the dianiline-based electron donor (,,','-((CH)POH)-4,4'-dianiline), RuCP is the light absorber [Ru((4,4'-(POHCH)-2,2'-bipyridine)(2,2'-bipyridine))], and Re(i) is the CO reduction catalyst, Re((4,4'-POHCH)-2,2'-bipyridine)(CO)Cl. Visible light excitation of the assembly in CO saturated solution resulted in CO reduction to CO. A steady-state photocurrent density of 65 μA cm was achieved under one sun illumination and an IPCE value of 1.9% was obtained with 450 nm illumination. The importance of the DA aniline donor in the assembly as an initial site for reduction of the RuCP excited state was demonstrated by an 8 times higher photocurrent generated with DA present in the surface film compared to a control without DA. Nanosecond transient absorption measurements showed that the expected reduced one-electron intermediate, RuCP, was formed on a sub-nanosecond time scale with back electron transfer to the electrode on the microsecond timescale which competes with forward electron transfer to the Re(i) catalyst at = 2.6 μs ( = 2.7 × 10 s).
我们在此描述了一种用于在0.1 M LiClO乙腈中将CO还原为CO的光阴极组件的制备和表征。该组件是在1.0μm厚的NiO介孔膜上通过基于Zr(IV)-膦酸酯桥联单元的逐层方法形成的。Zr(IV)桥联组件的结构缩写为NiO|-DA-RuCP -Re(i)，其中DA是基于二苯胺的电子供体（，，'-((CH)POH)-4,4'-二苯胺），RuCP是光吸收剂[Ru((4,4'-(POHCH)-2,2'-联吡啶)(2,2'-联吡啶))]，Re(i)是CO还原催化剂Re((4,4'-POHCH)-2,2'-联吡啶)(CO)Cl。在CO饱和溶液中对该组件进行可见光激发导致CO还原为CO。在一个太阳光照射下实现了65 μA cm的稳态光电流密度，在450 nm光照下获得了1.9%的IPCE值。与没有DA的对照相比，表面膜中存在DA时产生的光电流高出8倍，这证明了组件中DA苯胺供体作为RuCP激发态还原的初始位点的重要性。纳秒瞬态吸收测量表明，预期的还原单电子中间体RuCP在亚纳秒时间尺度上形成，在微秒时间尺度上有电子回传到电极，这与在 = 2.6 μs（ = 2.7 × 10 s）时向Re(i)催化剂的正向电子转移竞争。
