A liquid-hydrogen tanker truck fills up at a Linde AG hydrogen plant in Germany. As the oil-and-gas industry struggles to secure its place in a world shifting away from fossil fuels, major energy companies are making a grab for the rising hydrogen market. Hydrogen is expected to play a vital role in slashing emissions in a number of highly polluting industries that now face strict climate targets. The fuel, which burns clean when mixed with oxygen in a fuel cell, can power households, factories, cars, ships and planes. There…