First row transition metal catalysts for solar-driven water oxidation produced by electrodeposition

As our reliance on renewable energy resources increases, so will our need to store this energy in the form of chemical fuels to iron-out peaks and troughs in supply. Sunlight, the most plentiful source of renewable energy, is especially problematic in this regard as it is so diffuse. One way to convert solar irradiation to fuels effectively would be to develop large surface area photo-electrochemical devices that could use sunlight directly to split water into H2 and O2. However, in order to be feasible, such an approach requires that these devices (and their components) are extremely cheap. In this review, we will discuss catalysts for the water oxidation half-reaction of electrochemical water splitting that can be produced by electrodeposition (a technique well suited to large-scale, low-cost applications), and that are based on the comparatively plentiful and inexpensive first row transition metals. Special attention will be paid to the electrodeposition conditions used in the various examples given, and structure-function relationships for electrochemical water oxidation for the materials produced by these techniques will be elucidated

Kinematic artifacts in prestack depth migration.

Strong refraction of waves in the migration velocity model introduces kinematic artifacts¿coherent events not corresponding to actual reflectors¿into the image volumes produced by prestack depth migration applied to individual data bins. Because individual bins are migrated independently, the migration has no access to the bin component of slowness. This loss of slowness information permits events to migrate along multiple incident-reflected ray pairs, thus introducing spurious coherent events into the image volume. This pathology occurs for all common binning strategies, including common-source, common-offset, and common-scattering angle. Since the artifacts move out with bin parameter, their effect on the final stacked image is minimal, provided that the migration velocity model is kinematically correct. However, common-image gathers may exhibit energetic primary events with substantial residual moveout, even with the kinematically accurate migration velocity model

Recent progress towards the electrosynthesis of ammonia from sustainable resources

Ammonia (NH3) is a key commodity chemical of vital importance for fertilisers. It is made on an industrial scale via the Haber Bosch process, which requires significant infrastructure to be in place such that ammonia is generally made in large, centralized facilities. If ammonia could be produced under less demanding conditions, then there would be the potential for smaller devices to be used to generate ammonia in a decentralized manner for local consumption. Electrochemistry has been proposed as an enabling technology for this purpose as it is relatively simple to scale electrolytic devices to meet almost any level of demand. Moreover, it is possible to envisage electrosynthetic cells where water could be oxidised to produce protons and electrons at the anode which could then be used to reduce and protonate nitrogen to give ammonia at the cathode. If this nitrogen were sourced from the air, then the only required infrastructure for this process would be supplies of water, air and electricity, the latter of which could be provided by renewables. Hence an electrosynthetic cell for ammonia production could allow NH3 to be generated sustainably in small, low-cost devices requiring only minimal facilities. In this review, we describe recent progress towards such electrosynthetic ammonia production devices, summarizing also some of the seminal literature in the field. Comparison is made between the various different approaches that have been taken, and the key remaining challenges in the electrosynthesis of ammonia are highlighted

Russell Square: a lifelong resource for teaching and learning

A quarter of a century ago, in 1978, Birkbeck College’s Faculty of Continuing Education (FCE, then the Department for Extra-Mural Studies of the federal University) moved to the offices that it now occupies in numbers 26 and 25 Russell Square. Then, as now, FCE was the one of the largest and most active extra-mural departments of any British university, with an enormous range of courses covering virtually every subject taught in ‘internal’ university departments and many more besides 1. Some of these courses have, from time to time, used Russell Square as a learning resource. Many more staff and students alike have (along with thousands of local workers, tourists and residents) used the square’s gardens for relaxation and recovery, without reflecting on its origins or present significance. This Occasional Paper examines the past and present fabric of Russell Square (‘the Square’) as a resource for teaching and learning. It is a composite narrative assembled by FCE staff whose disciplines range from nature conservation through garden history and architectural history to social policy. It deconstructs the Square as an entity and attempts to decipher some of its ‘meanings’ that provide links between subjects taught within FCE. We hope that it will stimulate discussion about the way this single ‘place’ – our Square - can be ‘seen’ or interpreted in different ways for diverse purposes, and about the way that it can be used as a resource for teaching and learning across disciplines

Efficient electrocatalytic water oxidation at neutral and high pH by adventitious nickel at nanomolar concentrations

Electrolytic water oxidation using earth-abundant elements is a key challenge in the quest to develop cheap, large surface area arrays for solar-to-hydrogen conversion. There have been numerous studies in this area in recent years, but there remains an imperative to demonstrate that the current densities reported are indeed due to the species under consideration and not due to the presence of adventitious (yet possibly highly active) contaminants at low levels. Herein, we show that adventitious nickel at concentrations as low as 17 nM can act as a water oxidation catalyst in mildly basic aqueous solutions, achieving stable (tens of hours) current densities of 1 mA cm–2 at overpotentials as low as 540 mV at pH 9.2 and 400 mV at pH 13. This nickel was not added to the electrolysis baths deliberately, but it was found to be present in the electrolytes as an impurity by ICP-MS. The presence of nickel on anodes from extended-time bulk electrolysis experiments was confirmed by XPS. In showing that such low levels of nickel can perform water oxidation at overpotentials comparable to many recently reported water oxidation catalysts, this work serves to raise the burden of proof required of new materials in this field: contamination by adventitious metal ions at trace loadings must be excluded as a possible cause of any observed water oxidation activity

Adding content reporting to DSpace

This poster presents a content reporting add-on to DSpace, developed for AgResearch Ltd by the IRR support team at the University of Waikato's Information Technology Services Division. We outline the motivation for developing this add-on, give a high-level description of its implementation and report initial insights on its reception and uptake