Mesoporous metal oxide film electrodes consisting of derivatized 5.5 μm thick SnO2 films with an outer 4.3 nm shell of TiO2 added by atomic layer deposition (ALD) have been investigated to explore unbiased water splitting on p, n, and p+n type silicon substrates. Modified electrodes were derivatized by addition of the water oxidation catalyst, [Ru(bda)(4-O(CH2)3PO3H2)-pyr)2], 1, (pyr = pyridine; bda = 2,2'-bipyridine-6,6'-dicarboxylate), and chromophore, [Ru(4,4'-PO3H2-bpy) (bpy)2]2+, RuP2+, (bpy = 2,2'-bipyridine), which form 2:1 RuP2+/1 assemblies on the surface. At pH 5.7 in 0.1 M acetate buffer, these electrodes with a fluorine-doped tin oxide (FTO) back contact under ∼1 sun illumination (100 mW/cm2; white light source) perform efficient water oxidation with a photocurrent of 1.5 mA/cm2 with an 88% Faradaic efficiency (FE) for O2 production at an applied bias of 600 mV versus RHE ( ACS Energy Lett. , 2016 , 1 , 231 - 236 ). The SnO2/TiO2-chromophore-catalyst assembly was integrated with the Si electrodes by a thin layer of titanium followed by an amorphous TiO2 (Ti/a-TiO2) coating as an interconnect. In the integrated electrode, p+n-Si-Ti/a-TiO2-SnO2/TiO2|-2RuP2+/1, the p+n-Si junction provided about 350 mV in added potential to the half cell. In photolysis experiments at pH 5.7 in 0.1 M acetate buffer, bias-free photocurrents approaching 100 μA/cm2 were obtained for water splitting, 2H2O → 2H2 + O2. The FE for water oxidation was 79% with a hydrogen efficiency of ∼100% at the Pt cathode.
pan class="Chemical">Mesoporousn>an class="Chemical">metal oxide film electrodes consisting of derivatized 5.5 μm thick SnO2 films with an outer 4.3 nm shell of TiO2 added by atomic layer deposition (ALD) have been investigated to explore unbiased water splitting on p, n, and p+n type silicon substrates. Modified electrodes were derivatized by addition of the water oxidation catalyst, [Ru(bda)(4-O(CH2)3PO3H2)-pyr)2], 1, (pyr = pyridine; bda = 2,2'-bipyridine-6,6'-dicarboxylate), and chromophore, [Ru(4,4'-PO3H2-bpy) (bpy)2]2+, RuP2+, (bpy = 2,2'-bipyridine), which form 2:1 RuP2+/1 assemblies on the surface. At pH 5.7 in 0.1 M acetate buffer, these electrodes with a fluorine-doped tin oxide (FTO) back contact under ∼1 sun illumination (100 mW/cm2; white light source) perform efficient water oxidation with a photocurrent of 1.5 mA/cm2 with an 88% Faradaic efficiency (FE) for O2 production at an applied bias of 600 mV versus RHE ( ACS Energy Lett. , 2016 , 1 , 231 - 236 ). The SnO2/TiO2-chromophore-catalyst assembly was integrated with the Si electrodes by a thin layer of titanium followed by an amorphous TiO2 (Ti/a-TiO2) coating as an interconnect. In the integrated electrode, p+n-Si-Ti/a-TiO2-SnO2/TiO2|-2RuP2+/1, the p+n-Si junction provided about 350 mV in added potential to the half cell. In photolysis experiments at pH 5.7 in 0.1 M acetate buffer, bias-free photocurrents approaching 100 μA/cm2 were obtained for water splitting, 2H2O → 2H2 + O2. The FE for water oxidation was 79% with a hydrogen efficiency of ∼100% at the Pt cathode.
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Keywords:
Water splitting; core−shell; photoelectrochemistry; ruthenium; silicon; titanium dioxide
Authors: Degao Wang; Fujun Niu; Michael J Mortelliti; Matthew V Sheridan; Benjamin D Sherman; Yong Zhu; James R McBride; Jillian L Dempsey; Shaohua Shen; Christopher J Dares; Fei Li; Thomas J Meyer Journal: Proc Natl Acad Sci U S A Date: 2019-09-05 Impact factor: 11.205
Authors: Ana Belén Muñoz-García; Iacopo Benesperi; Gerrit Boschloo; Javier J Concepcion; Jared H Delcamp; Elizabeth A Gibson; Gerald J Meyer; Michele Pavone; Henrik Pettersson; Anders Hagfeldt; Marina Freitag Journal: Chem Soc Rev Date: 2021-11-15 Impact factor: 54.564