The Selective Electrochemical Conversion of Preactivated CO_2 to Methane

This work reports the selective electrochemical conversion of CO_2 to methane, the reverse reaction of fossil fuel combustion. This reaction is facilitated by preactivation of the CO_2 molecule with an N-heterocyclic carbene (NHC) to form a zwitterionic species in the first step. In the presence of Ni(cyclam)^(2+) and CF_3CH_2OH, this species is shown to undergo further electrochemical reduction of the bound-CO_2 fragment at glassy carbon cathodes in dichloromethane electrolyte solution. Labeling studies confirm the origin of the carbon and protons in the methane product are the preactivated CO_2 and trifluoroethanol respectively

Robust production of purified H-2 in a stable, self-regulating, and continuously operating solar fuel generator

The development of practical solar-driven electrochemical fuel generators requires the integration of light absorbing and electrochemical components into an architecture that must also provide easy separation of the product fuels. Unfortunately, many of these components are not stable under the extreme pH conditions necessary to facilitate ionic transport between redox reaction sites. By using a controlled recirculating stream across reaction sites, this work demonstrates a stable, self-regulating and continuous purified solar-hydrogen generation from near neutral pH electrolytes that yield continuous nearly pure H-2 streams with solar-fuel efficiencies above 6.2%

Discovery, benchmarking, characterization and integration of new materials for solar-fuels generators

The Joint Center for Artificial Photosynthesis (JCAP) was established in 2010 as a U.S. Department of Energy (DOE) Energy Innovation Hub. The JCAP mission is to demonstrate a scalable, integrated solar-fuels generator, which uses Earth-abundant elements and (with no wires) robustly produces fuel from the sun 10 times more efficiently than (current) crops. This presentation will describe how JCAP researchers use both directed and high-throughput approaches to discover light absorbers and catalysts for artificial photosynthesis, and how the performance of new materials is compared to known materials using rigorous benchmarking protocols. By using advanced characterization and computational techniques to understand and improve performance, promising materials are assembled into integrated structures that can be reliably produced and incorporated into scalable prototypes

Luquid membranes with light switches

Separation of solutes with liquid membranes becomes a powerful tool when the solute carriers are selectively activated photochemically

Ferrocene as an internal standard for electrochemical measurements

Electrochemistry is an increasingly popular technique for the characterization of new compounds. The basic thermodynamic quantity that is assigned to an electrode process is the standard or formal reduction potential (E^o or E^f). In aqueous solution the measurement of reduction potentials is facilitated by the use of reliable and universally accepted reference electrodes such as the normal hydrogen electrode (NHE) or the saturated calomel electrode (SCE). In many instances electrochemical measurements in water are impossible due to insolubility or instability of the compound. Unfortunately, no universal reference electrode exists for nonaqueous solvents

Ferrocene as an internal standard for electrochemical measurements

Electrochemistry is an increasingly popular technique for the characterization of new compounds. The basic thermodynamic quantity that is assigned to an electrode process is the standard or formal reduction potential (E^o or E^f). In aqueous solution the measurement of reduction potentials is facilitated by the use of reliable and universally accepted reference electrodes such as the normal hydrogen electrode (NHE) or the saturated calomel electrode (SCE). In many instances electrochemical measurements in water are impossible due to insolubility or instability of the compound. Unfortunately, no universal reference electrode exists for nonaqueous solvents