Hierarchical Integration of Photosensitizing Metal–Organic Frameworks and Nickel‐Containing Polyoxometalates for Efficient Visible‐Light‐Driven Hydrogen Evolution

Abstract

Metal-organic frameworks (MOFs) provide a tunable platform for hierarchically integrating multiple components to effect synergistic functions that cannot be achieved in solution. Here we report the encapsulation of a Ni-containing polyoxometalate (POM) [Ni4 (H2 O)2 (PW9 O34 )2 ](10-) (Ni4 P2 ) into two highly stable and porous phosphorescent MOFs. The proximity of Ni4 P2 to multiple photosensitizers in Ni4 P2 @MOF allows for facile multi-electron transfer to enable efficient visible-light-driven hydrogen evolution reaction (HER) with turnover numbers as high as 1476. Photophysical and electrochemical studies established the oxidative quenching of the excited photosensitizer by Ni4 P2 as the initiating step of HER and explained the drastic catalytic activity difference of the two POM@MOFs. Our work shows that POM@MOF assemblies not only provide a tunable platform for designing highly effective photocatalytic HER catalysts but also facilitate detailed mechanistic understanding of HER processes.

Metal–Organic Framework Based Catalysts for Hydrogen Evolution

“…[143] In this work, the UiO-MOF is used as both photo sensitizer and porous support to encapsulate POM units, due to its large tetrahedral and octahedral cavities. www.advancedsciencenews.com (designated Ni 4 P 2 @MOF-1a) (Ni 4 P 2 = Ni 4 (H 2 O) 2 (PW 9 O 34 ) 2 ] 10− ; ppy = 2-phenylpyridine; bpy = 2,2′-bipyridine; MOF = UiO = [Zr 6 (µ 3 -O) 4 (µ 3 -OH) 4 (L 1 ) 6 ](CO 2 CF 3 ) 6 ; L1 = [Ir(ppy) 2 (bpy)] + -derived carboxylate).…”

An Insight on the Electrocatalytic Mechanistic Study of Pristine Ni MOF (BTC) in Alkaline Medium for Enhanced OER and UOR

“…[16,[32][33][34][35][36] In this regard, numerous MOFs or MOFs derived metal oxides are progressively studied for the application in Li-ion battery, supercapacitors and sensors. [16,[32][33][34][35][36] In this regard, numerous MOFs or MOFs derived metal oxides are progressively studied for the application in Li-ion battery, supercapacitors and sensors.…”

A Novel Ruthenium-Decorating Polyoxomolybdate Cs3Na6H[MoVI14RuIV2O50(OH)2]·24H2O: An Active Heterogeneous Oxidation Catalyst for Alcohols

“…Noble metals containing polyoxometalates (POMs), in particular ruthenium (Ru)-incorporating structures [1], have been widely implemented in homo-/heterogeneous oxidation catalysis of both organic [2,3,4,5,6,7,8,9,10,11,12,13] and water-splitting reactions [14,15,16,17,18], and have therefore been attracting ever-increasing attention in recent decades. Since the discovery of the first Ru-containing POM [SiW 11 O 39 RuL] n− in 1989 [2], this domain has been further explored by the research groups of Neumann, Sadakane, Bonchio, Pope, Nomiya, Proust, Hill, Bond, Kortz, Bi and others [19].…”

“…Among them, the wholly inorganic Ru-containing POMs represent an important subclass, which had been studied previously but with only a few structures reported as compared to those with inorganic-organic hybrid Ru-containing POMs. Up until now, the majority of investigations in this area of research have been dominated by the preparations and characterizations of Ru-substituted or -sandwiched lacunary Keggin/Dawson-type heteropolytungstates [2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43], such as mono-Ru substituted polyanions [XW 11 O 39 Ru III (H 2 O)] n− (X = Si, Ge, P) [2,3,4,5,20,21,22,23,24,25] and [P 2 W 17 O 61 Ru III (H 2 O)] 5− [26,27,28], di-Ru-sandwiched/substituted polyanions {O[Ru IV (X)P 2 W 17 O 61 ] 2 } 16− (X = OH, Cl) [27], {[(XZnRu 2 III (OH)(H 2 O)](ZnW 9 O 34 ) 2 } n− (X = W, Zn) [29,30,…”