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Eisenberg, Richard

Publications and source records attributed to Eisenberg, Richard.

5 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Addressing the challenge of carbon-free energy

This century will witness a major transformation in how energy is acquired, stored, and utilized globally. The impetus for this change comes from the deep impacts that both developed and developing societies have had on our planet's environment during the past century, and the projections going forward of what will happen if we do not act transformativelywithin the next 2 decades. This paper describes the basis for a meeting held in October 2018 on the need for decarbonization in our energy landscape, and specifically the status and challenges of the science that provides the foundation for such technology. Within the realm of decarbonization in energy generation lies the science of solar energy conversion using new or improved photovoltaic materials and artificial photosynthesis for water splitting and other energy-storing reactions. The intimately related issue of renewable energy storage is being addressed with new strategies, materials, and approaches under current investigation and development. The need to improve the interactions between scientists working on these connected but separately considered challenges and on the transition of scientific achievement to practical application was also addressed, with specific efforts enumerated.

climate change↗
DOE OSTI2019

Methods for producing hydrogen using nanoparticle-catalyst mixtures

Provided are compositions for and methods of producing hydrogen. For example, the compositions comprise nanocrystals, a catalyst, a source of electrons, and an aqueous medium. The nanocrystals, catalyst, aqueous medium, and, optionally, the source of electrons are present as a mixture. The methods produce hydrogen by exposing the compositions to electromagnetic radiation (e.g., solar flux).

08 HYDROGEN↗
DOE OSTI2018

Probing the Electron Accepting Orbitals of Ni-Centered Hydrogen Evolution Catalysts with Noninnocent Ligands by Ni L-Edge and S K-Edge X-ray Absorption

Here, the valence electronic structure of several square planar Ni-centered complexes, previously shown to catalyze the hydrogen evolution reaction, are characterized using S K-edge and Ni L-edge X-ray absorption spectroscopy and electronic structure calculations. Measurement of the atomic Ni 3d and S 3p contributions enables assessment of the metal–ligand covalency of the electron accepting valence orbitals and yields insight into the ligand-dependent reaction mechanisms proposed for the catalysts. The electron accepting orbital of the Ni(abt) 2 (abt = 2-aminobenzenethiolate) catalyst is found to have large ligand character (80%), with only 9% S 3p (per S) character, indicating delocalization over the entire abt ligand. Upon two proton-coupled reductions to form the Ni(abt-H) 2 intermediate, the catalyst stores 1.8 electrons on the abt ligand, and the ligand N atoms are protonated, thus supporting its role as an electron and proton reservoir. The electron accepting orbitals of the Ni(abt-H) 2 intermediate and Ni(mpo) 2 (mpo = 2-mercaptopyridyl- N -oxide) catalyst are found to have considerably larger Ni 3d (46–47%) and S 3p (17–18% per S) character, consistent with an orbital localized on the metal–ligand bonds. This finding supports the possibility of metal-based chemistry, resulting in Ni–H bond formation for the reduced Ni(abt-H) 2 intermediate and Ni(mpo) 2 catalyst, a critical reaction intermediate in H 2 generation.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2017

Semiconductor quantum dot-sensitized rainbow photocathode for effective photoelectrochemical hydrogen generation

We discuss the fabrication of CdSe quantum dot (QD)-sensitized photocathodes on NiO-coated indium tin oxide (ITO) electrodes and their H 2 -generating ability upon light irradiation. A well-established spin-coating approach was used to deposit CdSe QD stock solution onto the surface of NiO/ITO electrodes, thereby leading to the construction of various CdSe QD-sensitized photocathodes. The present report includes the construction of rainbow photocathodes by spin-coating different-sized QDs in a sequentially layered manner, thereby creating an energetically favorable gradient for charge separation. The resulting rainbow photocathodes with forward energetic gradient for charge separation and subsequent electron transfer to a solution-based hydrogen-evolving catalyst (HEC) exhibit good light-harvesting ability and enhanced photoresponses compared with the reverse rainbow photocathodes under white LED light illumination. Under minimally optimized conditions, a photocurrent density of as high as 115 μA•cm –2 and a Faradaic efficiency of 99.5% are achieved, which is among the most capable QD-based photocathode water-splitting systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗