Tag: hydrogen gas

Producing hydrogen from seawater

Producing hydrogen from seawater

McGill scientists have identified potential method for producing hydrogen from the oceans.

In her research on bone tissue engineering, Dr. Marta Cerruti has worked for years with graphene, a single sheet of carbon atoms with incredible properties – electrical conductivity and the ability to support tremendous weight. Now, her quest to improve its qualities has opened the door to a possible solution to one of the challenges of producing hydrogen from seawater.

Cerruti, a professor of materials engineering at McGill University, explained that while graphene is structurally sound, “one sheet of atoms is not something you can easily work with.” In fact, piling the sheets up results in, basically, pencil lead.

Searching for a way to make an easy-to-handle structure, Cerruti’s PhD student Yiwen Chen combined graphene with oxygen in a suspension with water to create reduced graphene oxide (GO), a porous, three-dimensional, electrically conductive scaffold. Cerruti suggested a further modification, with GO flakes stacked on the pore walls, “which allowed us to exploit another interesting property of GO – it creates a membrane that allows water through but no other molecules.”

When she canvassed her team for suggestions on how best to test the new scaffold, Gabriele Capilli, a post-doctoral fellow in her lab, suggested seawater electrolysis, a process similar to others he worked on while doing his PhD. It turns out the new GO “selective scaffold” has the potential to improve the process of producing hydrogen from the ocean. The team’s findings were published recently in the journal ACS Nano.

In conventional electrolysis, chloride ions in seawater penetrate the electrode and interact with the catalyst, creating hypochlorite ions, an unwanted byproduct that poisons the catalyst, Cerruti explained. Using X-ray phase contrast imaging at the Canadian Light Source at the University of Saskatchewan, Chen confirmed the GO scaffold had the right structure, with closed GO pores enclosing cobalt oxide nanoparticles as the catalyst. “We saw what we wanted to see.” Electrochemical tests performed in the laboratory of collaborator Thomas Szkopek (electrical engineering, McGill) confirmed the scaffold worked as expected to block unwanted ions.

Read more on the CLS website

Image: Gabriele Capilli, Marta Cerruti, and Thomas Szkopek (l to r), in their lab at McGill University.

Powering the future of clean energy

Powering the future of clean energy

Hydrogen gas can be used to power vehicles and has the potential to provide electricity to homes

The global quest for clean energy is championed by researchers in Canada who are focused on harnessing the potential of hydrogen.

The idea of the hydrogen economy was first proposed 50 years ago as a way to combat the negative effects of fossil fuels. Its future is the focus of new research from the University of Toronto’s Thermofluids for Energy and Advanced Materials (TEAM) lab, whose work relied on the Canadian Light Source (CLS) at the University of Saskatchewan to visualize performance.

Read more on the Canadian Light Source website

Image: Adam Webb (CLS), Sergey Gasilov (CLS), Manojkumar Balakrishnan (U of T), Jason Keonhag Lee (U of T), Denise Miller (CLS), Kieran Fahy (U of T) on the BMIT beamline at CLS.

How a new electrocatalyst enables ultrafast reactions

How a new electrocatalyst enables ultrafast reactions

The work provides rational guidance for the development of better electrocatalysts for applications such as hydrogen-fuel production and long-range batteries for electric vehicles.

The oxygen evolution reaction (OER) is the electrochemical mechanism at the heart of many processes relevant to energy storage and conversion, including the splitting of water to generate hydrogen fuel and the operation of proposed long-range batteries for electric vehicles. Because the OER rate is a limiting factor in such processes, highly active OER electrocatalysts with long-term stability are being sought to increase reaction rates, reduce energy losses, and improve cycling stability. Catalysts incorporating rare and expensive materials such as iridium and ruthenium exhibit good performance, but an easily prepared, efficient, and durable OER catalyst based on earth-abundant elements is still needed for large-scale applications.

Key insight: shorter O-O bonds
In an earlier study, a group led by John Goodenough (2019 Nobel laureate in chemistry) measured the OER activities of two compounds with similar structures: CaCoO3 and SrCoO3. They found that the CaCoO3 exhibited higher OER activity, which they attributed to its shorter oxygen–oxygen (O-O) bonds. Inspired by this, members of the Goodenough group have now analyzed a metallic layered oxide, Na0.67CoO2, which has an even more compact structure than CaCoO3. X-ray diffraction (XRD) experiments performed at the Advanced Photon Source (APS) confirmed that the shortest O-O separation in Na0.67CoO2 is 2.30 Å, compared to 2.64 Å for CaCoO3. The researchers then compared the OER performance of Na0.67CoO2 with IrO2, Co3O4, and Co(OH)2. They found that Na0.67CoO2 exhibited the highest current density, the lowest overpotential (a measure of thermodynamic energy loss), and the most favorable Tafel slope (sensitivity of the electric current to applied potential). The Na0.67CoO2 also showed excellent stability under typical operating conditions.

>Read more on the Advanced Light Source website

Image: (extract, full image here) A new electrocatalyst prepared for this study, Na0.67CoO2, consists of two-dimensional CoO2 layers separated by Na layers (not shown). The Co ions (blue spheres) have four different positions (Co1-Co4), and the distorted Co–O octahedra have varying oxygen–oxygen (O-O) separations (thick red lines connecting red spheres). All of the O-O bonds are shorter than 2.64 Å (the length of the corresponding bonds in a comparable material), and the shortest bonds are less than 2.40 Å. It turns out that O-O separation has a strong effect on the oxygen evolution reaction (OER) in this material.

Toward better motors with X-ray light

Toward better motors with X-ray light

Making Switzerland’s road traffic fit for the future calls for research, first and foremost. In the large-scale research facilities of PSI, chemists and engineers are investigating how to improve the efficiency of motors and reduce their emissions.

“The overall transportation system of Switzerland in 2040 is efficient in all aspects.” The primary strategic goal of the Federal Department of the Environment, Transport, Energy and Communications (DETEC) sounds good. The subordinate Swiss Federal Office of Energy (SFOE) specifies that vehicular traffic should pollute the environment less and become more energy-efficient and climate-friendly. Switzerland has set an ambitious goal for itself: to be climate-neutral by 2050.
This is a major challenge. According to the most recent “microcensus” on mobility from 2015, every person living in Switzerland travels around 24,850 kilometres per year. A high number, which also includes trips abroad. In everyday life and within Switzerland, the average per person is nearly 37 kilometres per day – and rising.
According to the Federal Office for the Environment (FOEN), cars, trucks, and buses produce three-fourths of the greenhouse gas emissions in the transportation sector. From this it follows: Whether or not the nation achieves its goal depends heavily on the motors used in these modes of transportation. Their CO2 emissions must be radically reduced. This is precisely the starting point for researchers at PSI and other institutions.

> Read more on the Swiss Light Source (PSI) website

Image: Passenger cars powered by hydrogen fuel cells have a greater range than electric cars, but they are less efficient. PSI researchers want to change that.
Credit: Adobe Stock/Graphic: Stefan Schulze-Henrichs

2017’s Top-10 Discoveries and Scientific Achievements

2017’s Top-10 Discoveries and Scientific Achievements

Each year we compile a list of the biggest advances made by scientists, engineers, and those who support their work at the U.S. Department of Energy’s Brookhaven National Laboratory. From unraveling new details of the particle soup that filled the early universe to designing improvements for batteries, x-ray imaging, and even glass, this year’s selections span a spectrum of size scales and fields of science. Read on for a recap of what our passion for discovery has uncovered this year.  (…)

4. Low-Temperature Hydrogen Catalyst

Brookhaven chemists conducted essential studies to decipher the details of a new low-temperature catalyst for producing high-purity hydrogen gas. Developed by collaborators at Peking University, the catalyst operates at low temperature and pressure, and could be particularly useful in fuel-cell-powered cars. The Brookhaven team analyzed the catalyst as it was operating under industrial conditions using x-ray diffraction at the National Synchrotron Light Source (NSLS). These operando experiments revealed how the configuration of atoms changed under different operating conditions, including at different temperatures. The team then used those structural details to develop models and a theoretical framework to explain why the catalyst works so well, using computational resources at Brookhaven’s Center for Functional Nanomaterials (CFN).

 >Read more on the NSLS-II website