Single Crystal and Magnetic Characterization of Iodobarlowite Cu 4 (OH) 6 FI: A Kagome Lattice Synthesized from a 2-D Triangular Precursor
A new synthesis method of oxides.
Evenson, Ryan J.↗
Engineering topics
Nocera, Daniel G.
Publications and source records attributed to Nocera, Daniel G..
A Straightforward Model for Quantifying Local pH Gradients Governing the Oxygen Evolution Reaction
The production and consumption of protons by an electrocatalyst will, under certain conditions, generate localized microenvironments with properties distinct from those of the bulk solution. These local properties are particularly impactful for reactions involving proton-coupled electron transfer, where the generation of locally basic or acidic environments may significantly influence the energy efficiency and reaction selectivity of the electrocatalyst. Whereas local pH environments have been observed and characterized in reductive half-reactions, including the CO 2 reduction and hydrogen evolution reactions, the incompatibility of conventional techniques and materials has limited studies in oxidative half-reactions, including the oxygen evolution reaction (OER), which provides the reducing equivalents for solar-to-fuels electrolysis. With the straightforward parameters bulk pH, buffer composition and pK a , and mass transport, we develop a model for describing local pH as a function of current density regardless of the microscopic details of the mechanism. Using an acid-stable PbO x OER catalyst, we observe the formation and dissipation of pH gradients during the OER and validate the model with voltammetric and potentiometric studies. Here, the model predicts how local acidic environments can develop over a narrow OER current density window, thus providing further motivation for the development of OER catalysts that are stable to acid, even when operating in basic aqueous conditions. More generally, the model is not restricted to the OER and is useful for determining the onset of local pH gradients for other electrocatalytic reactions that involve the consumption or generation of protons in energy conversion reactions.
Anions↗
Realizing Ciamician’s Energy Future
Giacomo Ciamician imagined a future sustained only by sunlight, air and water - the Artificial Leaf and Bionic Leaf enable such a future. The Artificial Leaf uses sunlight to split H 2 O to H 2 and O 2 . The Bionic Leaf-C takes the H 2 from the catalysts of the Artificial Leaf and combines it with CO 2 in air to make biomass and liquid fuels at efficiencies that are 10 to 100 times greater than natural photosynthesis. Extending the approach, the Bionic Leaf-N combines the H 2 from the Artificial Leaf with N 2 in the air to make a sustainable fertilizer. Finally, these discoveries of distributed Fischer-Tropsch and Haber-Bosch processes are particularly useful to the underserved of the world, where large infrastructures for fuel and food production do not exist
Nocera, Daniel G.↗
Sustainable Energy Production and Manufacturing Using Only Sunlight, Air, and Water
A report on the discovery of the Bionic Leaf
Nocera, Daniel G.↗
Oxidation Chemistry of Bicarbonate and Peroxybicarbonate: Implications for Carbonate Management in Energy Storage
Carbonate formation presents a major challenge to energy storage applications based on low-temperature CO 2 electrolysis and recyclable metal–air batteries. While direct electrochemical oxidation of (bi)carbonate represents a straightforward route for carbonate management, knowledge of the feasibility and mechanisms of direct oxidation is presently lacking. Herein, we report the isolation and characterization of the bis(triphenylphosphine)iminium salts of bicarbonate and peroxybicarbonate, thus enabling the examination of their oxidation chemistry. Infrared spectroelectrochemistry combined with time-resolved infrared spectroscopy reveals that the photoinduced oxidation of HCO 3 – by an Ir(III) photoreagent results in the generation of the short-lived bicarbonate radical in less than 50 ns. The highly acidic bicarbonate radical undergoes proton transfer with HCO 3 – to furnish the carbonate radical anion and H 2 CO 3 , leading to the eventual release of CO 2 and H 2 O, thus accounting for the appearance of H 2 O and CO 2 in both electrochemical and photochemical oxidation experiments. Here, the back reaction of the carbonate radical subsequently oxidizes the Ir(II) photoreagent, leading to carbonate. In the absence of this back reaction, dimerization of the carbonate radical provides entry into peroxybicarbonate, which we show undergoes facile oxidation to O 2 and CO 2 . Together, the results reported identify tangible pathways for the design of catalysts for the management of carbonate in energy storage applications.
25 ENERGY STORAGE↗