Our investment decisions and growth strategy are guided by an emphasis on sustainable business practices and full compliance with laws, regulations and internal standards.
Strong financial performance is key to the sustainable growth of our business and our future success. Our stakeholders around the world expect us to deliver on our financial commitments by generating and distributing economic value. To that end, we are focused on growing our earnings by 7% to 10% over time while also returning 50% of our discretionary free cash flow to shareholders. We believe this approach, in combination with investing for growth in our businesses, will allow us to maintain our reputation as a leader in our markets and be well-positioned to respond to the evolving needs of our customers.
We had strong financial performance in 2021, driven by the successful execution of our business strategy and a more favorable economic climate that raised the demand for our products and process solutions. We delivered adjusted earnings per share of $5.02. Our operating cash flow was $257 million, and we generated a record discretionary free cash flow (DFCF) of $353 million. From FY 2015 to FY 2021, we delivered significant shareholder value - returning 64% of DFCF to shareholders, exceeding the 50% target we set.
With our “Creating for Tomorrow” strategy, we will leverage our strengths and invest for advantaged growth. We drive growth across our portfolio through capital investments and strategic acquisitions that enhance our competitive position. In 2021, we achieved more than two-thirds of our 2025 goal to invest $1 billion in capital and technology.
We invested in the high-growth carbon nanotubes (CNTs) business serving the electric vehicle (EV) market by acquiring Shenzhen Sanshun Nano New Materials Co. This highly synergistic acquisition complements our existing portfolio of conductive carbon additives and creates a significant opportunity to deliver new innovate formulated solutions for improved battery performance and energy performance solutions, particularly in China, which is the largest and fastest-growing global EV market. These different products and formulations will create improved and differentiated performance in batteries and are expected to deliver a material contribution for our growth in the future.
We made significant capital investments in emissions control technology at several of our carbon black manufacturing facilities. These investments consist of projects in Xingtai, China, and Franklin and Ville Platte, LA, USA, which will result in improved air quality through the reduction of NOX and SOX emissions.