Global snapshot of the effects of the COVID-19 pandemic on the research activities of materials scientists between Spring and Autumn 2020.

We conducted a global survey on the effects of the COVID-19 pandemic on the research activities of materials scientists by distributing a questionnaire on 9 October 2020 with a response deadline of 23 October 2020. The questions covered issues such as access to labs, effectiveness of online conferences, and effects on doctoral students for the period covering the first lockdowns until the relaxation of restrictions in late September 2020 in many countries. The survey also included online interviews with eminent materials scientists who shared their local experiences during this period. The interviews were compiled as a series of audio conversations for The STAM Podcast that is freely available worldwide. Our findings included that the majority of institutes were not prepared for such a crisis; researchers in China, Japan, and Singapore were able to resume research much quicker - for example after approximately one month in Japan - than their counterparts in the US and Europe after the first lockdowns; researchers adapted to using virtual teleconferencing to maintain contact with colleagues; and doctoral students were the hardest hit by the pandemic with deep concerns about completing their research and career prospects. We hope that the analysis from this survey will enable the global materials science community to learn from each other's experiences and move forward from the unprecedented circumstances created by the pandemic.

Ability of hydrogen storage CeNi5-x Ga x and Mg2Ni alloys to hydrogenate acetylene.

Hydrogen storage properties and reactivity for hydrogenation of acetylene in a series of CeNi5-x Ga x (x = 0, 0.5, 0.75, 1, 1.25, 1.5) alloys and Mg2Ni were determined and compared. The structure of CeNi5 (CaCu5 type) was maintained up to CeNi3.5Ga1.5 when Ni was replaced by Ga. The replacement facilitated hydrogenation absorption by creating larger interstitial spaces through expansion of the lattice, allowing CeNi4.25Ga0.75 to absorb the greatest proportion of hydrogen atoms among the alloys under the same conditions. The results showed that the absorbed hydrogen in CeNi3.75Ga1.25 improved reactivity. In contrast, Mg2Ni formed a hydride upon hydrogenation of acetylene and thus possessed much lower activity. The difference of the activity of absorbed hydrogen between CeNi5-x Ga x and Mg2Ni was confirmed from transient response tests under reaction gases alternately containing He and H2.

Fast Oxidation of Porous Cu Induced by Nano-Twinning.

The fcc lattice of porous Cu prepared by dealloying Al2Cu with HCl aqueous solution exhibits a high density of twinning defects with an average domain size of about 3 nm along the ⟨111⟩ directions. The high density of twinning was verified by X-ray diffraction and qualitatively interpreted by a structural model showing the 5% probability of twinning defect formation. Most of the twinning defects disappeared after annealing at 873 K for 24 h. Twinned Cu reveals much faster oxidation rate in comparison to that without (or with much fewer) twinning defects, as shown by X-ray diffraction and hydrogen differential scanning calorimetry. Using ab initio DFT calculations, we demonstrate that twinning defects in porous Cu are able to form nucleation centers for the growth of Cu2O. The geometry of the V-shaped edges on the twinned {211} surfaces is favorable for formation of the basic structural elements of Cu2O. The fast oxidation of porous Cu prepared by dealloying can thus be explained by the fast formation of the Cu2O nucleation centers and their high density.